Expression of delayed cell death (DCD) in the progeny of fish cells surviving 2,4-dichloroaniline (2,4-DCA) exposure

International Nuclear Information System (INIS)

Kilemade, Michael; Mothersill, Carmel

2003-01-01

Interest in and concern for the quality of the environment has prompted a great deal of research into methods of measuring and assessing changes in it. One problem of major interest is that of increasing amounts of mutagenic/carcinogenic chemicals generated and released into marine and freshwater ecosystems. Numerous techniques involving whole animals and cell culture for these genotoxic changes have been devised to assay specific chemicals. Little has been done to determine the effects of potential genotoxicants on aquatic organisms. The purpose of this study was to investigate if 2,4-Dichloroaniline (2,4-DCA) (CASRN: 554-00-7), induced delayed cell death (DCD) or delayed reproductive cell death a.k.a. as lethal mutations in a teleost cell line, CHSE-214. Delayed expression of cell death in the progeny of cells, which survived a toxic insult, was first shown for ionizing radiation and is one of the signs of induced genomic instability. The survival of cells initially treated with 2,4-DCA and the survival of their progeny were determined. When cells are exposed to a toxic insult, the component cells of a normal appearing survivor colony or clone were commonly thought to have proliferative capacity equivalent to that of the untreated cells. In this study, however, it was found that CHSE-214 cells surviving 2,4-DCA exposure carried heritable lethal defects, which came to light only after numerous apparently successful divisions, in the form of plating efficiencies, which were reduced below those of the untreated, control cells. DCD expression did not appear to be dose-dependent with poor cell survival occurring at the lower end of 2,4-DCA exposure and remained constant until recovering to something like 60% of the controls. A study of the CHSE-214 kinetics post-exposure showed that the apparent reduced growth rate of the cells was due to reduced numbers of reproductively viable cells in the population. Results showed that the expression of DCD occurred persistently

Time delay and noise explaining the behaviour of the cell growth in fermentation process

Energy Technology Data Exchange (ETDEWEB)

Ayuobi, Tawfiqullah; Rosli, Norhayati [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia); Bahar, Arifah [Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Salleh, Madihah Md [Department of Biotechnology Industry, Faculty of Biosciences and Bioengineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

2015-02-03

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

Time delay and noise explaining the behaviour of the cell growth in fermentation process

Science.gov (United States)

Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah; Salleh, Madihah Md

2015-02-01

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

Time delay and noise explaining the behaviour of the cell growth in fermentation process

International Nuclear Information System (INIS)

Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah; Salleh, Madihah Md

2015-01-01

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process

The Consequence of Delayed Fixation on Subsequent Preservation of Urine Cells

Directory of Open Access Journals (Sweden)

Hussain G. Ahmed,

2011-01-01

Full Text Available Objectives: Degenerative changes caused by delays in urine preservation contribute to false-negative and false-positive interpretation of urothelial disease in cytology. The aim of this study is to assess whether the delay of fixation of urine samples makes any significant difference to urine cytology and morphology, and the limit of acceptability of delay for routine use in the hospital laboratory.Methods: Three cell collection fluids were evaluated by analyzing the preservation and degeneration of cells in urine samples. In this study, 50 voided urine specimens were taken at random from females complaining of vaginal discharge. Each specimen was divided into three sterile containers. The first was immediately centrifugated and the deposit was smeared onto a cleaned micro slide and immediately fixed into 95�0ethyl alcohol for 15 minutes. The remaining two were prepared in the same manner, however, the second after two hours of collection and the third after four hours of collection. The degree of degeneration and thus the preservation were assessed by a table of chosen criteria, then ranked and analyzed using Friedman's nonparametric test, atp=0.05.Results: The results showed a significant difference between the preservation and the delay in urine fixation, p<0.0001.Conclusion: Any delay in fixation of urine specimen for cytology affects the preservation of cells, which may result in miss diagnosis. It is recommended that urine samples for cytology should be fixed immediately after collection.

Delayed animal aging through the recovery of stem cell senescence by platelet rich plasma.

Science.gov (United States)

Liu, Hen-Yu; Huang, Chiung-Fang; Lin, Tzu-Chieh; Tsai, Ching-Yu; Tina Chen, Szu-Yu; Liu, Alice; Chen, Wei-Hong; Wei, Hong-Jian; Wang, Ming-Fu; Williams, David F; Deng, Win-Ping

2014-12-01

Aging is related to loss of functional stem cell accompanying loss of tissue and organ regeneration potentials. Previously, we demonstrated that the life span of ovariectomy-senescence accelerated mice (OVX-SAMP8) was significantly prolonged and similar to that of the congenic senescence-resistant strain of mice after platelet rich plasma (PRP)/embryonic fibroblast transplantation. The aim of this study is to investigate the potential of PRP for recovering cellular potential from senescence and then delaying animal aging. We first examined whether stem cells would be senescent in aged mice compared to young mice. Primary adipose derived stem cells (ADSCs) and bone marrow derived stem cells (BMSCs) were harvested from young and aged mice, and found that cell senescence was strongly correlated to animal aging. Subsequently, we demonstrated that PRP could recover cell potential from senescence, such as promote cell growth (cell proliferation and colony formation), increase osteogenesis, decrease adipogenesis, restore cell senescence related markers and resist the oxidative stress in stem cells from aged mice. The results also showed that PRP treatment in aged mice could delay mice aging as indicated by survival, body weight and aging phenotypes (behavior and gross morphology) in term of recovering the cellular potential of their stem cells compared to the results on aged control mice. In conclusion these findings showed that PRP has potential to delay aging through the recovery of stem cell senescence and could be used as an alternative medicine for tissue regeneration and future rejuvenation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Carbonate fuel cell and components thereof for in-situ delayed addition of carbonate electrolyte

Science.gov (United States)

Johnsen, Richard [Waterbury, CT; Yuh, Chao-Yi [New Milford, CT; Farooque, Mohammad [Danbury, CT

2011-05-10

An apparatus and method in which a delayed carbonate electrolyte is stored in the storage areas of a non-electrolyte matrix fuel cell component and is of a preselected content so as to obtain a delayed time release of the electrolyte in the storage areas in the operating temperature range of the fuel cell.

Staphylococcus aureus Lpl Lipoproteins Delay G2/M Phase Transition in HeLa Cells.

Science.gov (United States)

Nguyen, Minh-Thu; Deplanche, Martine; Nega, Mulugeta; Le Loir, Yves; Peisl, Loulou; Götz, Friedrich; Berkova, Nadia

2016-01-01

The cell cycle is an ordered set of events, leading to cell growth and division into two daughter cells. The eukaryotic cell cycle consists of interphase (G 1 , S, and G 2 phases), followed by the mitotic phase and G 0 phase. Many bacterial pathogens secrete cyclomodulins that interfere with the host cell cycle. In Staphylococcus aureus four cyclomodulins have been described so far that all represent toxins and are secreted into the culture supernatant. Here we show that the membrane-anchored lipoprotein-like proteins (Lpl), encoded on a genomic island called νSaα, interact with the cell cycle of HeLa cells. By comparing wild type and lpl deletion mutant it turned out that the lpl cluster is causative for the G2/M phase transition delay and also contributes to increased invasion frequency. The lipoprotein Lpl1, a representative of the lpl cluster, also caused G2/M phase transition delay. Interestingly, the lipid modification, which is essential for TLR2 signaling and activation of the immune system, is not necessary for cyclomodulin activity. Unlike the other staphylococcal cyclomodulins Lpl1 shows no cytotoxicity even at high concentrations. As all Lpl proteins are highly conserved there might be a common function that is accentuated by their multiplicity in a tandem gene cluster. The cell surface localized Lpls' suggests a correlation between G2/M phase transition delay and host cell invasion.

The epidermal cell kinetic response to ultraviolet B irradiation combines regenerative proliferation and carcinogen associated cell cycle delay

Energy Technology Data Exchange (ETDEWEB)

Olsen, W.M.; Kirkhus, B. (Oslo Univ. (Norway))

1989-09-01

The cell cycle traverse of epidermal basal cells 24 h after in vivo exposure of ultraviolet B (UVB) irradiation was studied by immunochemical staining of incorporated bromodeoxyuridine (BrdU) and bivariate BrdU/DNA flow cytometric analysis. The results were compared with the cell kinetic patterns following topical application of the skin carcinogen methylnitrosourea (MNU) as well as the skin irritant cantharidin. The cell cycle traverse in hairless mouse epidermis 24 h after in vivo exposure to UVB seemed to be a combination of the cell kinetic effects following chemical skin carcinogens and skin irritants. UVB irradiation induced both a delay in transit time through S phase, probably due to DNA damage and subsequent repair, as well as a reduction in the total cell cycle time consistent with rapid regenerative proliferation. (author).

TGF-β's delay skeletal muscle progenitor cell differentiation in an isoform-independent manner

International Nuclear Information System (INIS)

Schabort, Elske J.; Merwe, Mathilde van der; Loos, Benjamin; Moore, Frances P.; Niesler, Carola U.

2009-01-01

Satellite cells are a quiescent heterogenous population of mononuclear stem and progenitor cells which, once activated, differentiate into myotubes and facilitate skeletal muscle repair or growth. The Transforming Growth Factor-β (TGF-β) superfamily members are elevated post-injury and their importance in the regulation of myogenesis and wound healing has been demonstrated both in vitro and in vivo. Most studies suggest a negative role for TGF-β on satellite cell differentiation. However, none have compared the effect of these three isoforms on myogenesis in vitro. This is despite known isoform-specific effects of TGF-β1, -β2 and -β3 on wound repair in other tissues. In the current study we compared the effect of TGF-β1, -β2 and -β3 on proliferation and differentiation of the C2C12 myoblast cell-line. We found that, irrespective of the isoform, TGF-β increased proliferation of C2C12 cells by changing the cellular localisation of PCNA to promote cell division and prevent cell cycle exit. Concomitantly, TGF-β1, -β2 and -β3 delayed myogenic commitment by increasing MyoD degradation and decreasing myogenin expression. Terminal differentiation, as measured by a decrease in myosin heavy chain (MHC) expression, was also delayed. These results demonstrate that TGF-β promotes proliferation and delays differentiation of C2C12 myoblasts in an isoform-independent manner

Delayed K562 cell apoptosis promoted by cleaved LyGDI after 60Co γ-rays irradiation

International Nuclear Information System (INIS)

Sun Huali; Duan Weiming; Shao Yanyan; Xiao Hainan; Zhou Xinwen

2010-01-01

Objective: To elucidate the function and regulatory mechanism of LyGDI involved delayed cell death in the human K562 cells and HL-60 cells induced by 60 Co γ-rays. Methods: Erythrosine B cells staining was used to count the apoptosis rate. PI staining and flow cytometry were applied to check the cell cycle. The expression of LYGDI and Rac1 was resolved by Western blot by using monoclonal antibody of LyGDI and Rac1. The distribution of Rac1 protein in cells was observed with immunofluorescence by using the confocal microscope. Results: The K562 cells showed G 2 /M phase arrest and the percent age was 71.3%. The apoptosis rate was very low at early post-irradiation stage in the K562 cells. The apoptosis rate was 14% in the K562 cells at 24 h post-irradiation with 8 Gy of γ-rays, and delayed cell apoptosis was present. LyGDI was cleaved in the K562 cells irradiated by 4 Gy 60 Co γ-rays after 24 hours post-irradiation. The expression of Rac1 protein was not altered at all, but the distribution was changed in the irradiated cells while the Rac1 protein moved to cell membrane and a little in cell nucleus. The Rac1 was activated with the losing the binding affinity with the LyGDI. Conclusion: LyGDI could promote the delayed cell apoptosis, which is through the activation of the Rac1. (authors)

Nucleolar re-activation is delayed in mouse embryos cloned from two different cell lines

DEFF Research Database (Denmark)

Svarcova, Olga; Dinnyes, A.; Polgar, Z.

2009-01-01

displayed early NPBs transformation. In conclusion, despite normal onset of EGA in cloned embryos, activation of functional nucleoli was one cell cycle delayed in NT embryos. NT-MEF embryos displayed normal targeting but delayed activation of nucleolar proteins. Contrary, in NT-HM1 embryos, both......Aim of this study was to evaluate and compare embryonic genome activation (EGA) in mouse embryos of different origin using nucleolus as a marker. Early and late 2-cell and late 4-cell stage embryos, prepared by in vitro fertilization (IVF), parthenogenetic activation (PG), and nuclear transfer...... ofmouse embryonic fibroblast (MEF) and mouse HM1 emryonic stem cells (HM1), were processed for autoradiography following 3H-uridine incubation (transcriptional activity), transmission electron microscopy (ultrastructure) and immunofluorescence (nucleolar proteins; upstream binding factor, UBF...

Chronic Alcohol Ingestion Delays T Cell Activation and Effector Function in Sepsis.

Science.gov (United States)

Margoles, Lindsay M; Mittal, Rohit; Klingensmith, Nathan J; Lyons, John D; Liang, Zhe; Serbanescu, Mara A; Wagener, Maylene E; Coopersmith, Craig M; Ford, Mandy L

2016-01-01

Sepsis is the leading cause of death in intensive care units in the US, and it is known that chronic alcohol use is associated with higher incidence of sepsis, longer ICU stays, and higher mortality from sepsis. Both sepsis and chronic alcohol use are associated with immune deficits such as decreased lymphocyte numbers, impaired innate immunity, delayed-type hypersensitivity reactions, and susceptibility to infections; however, understanding of specific pathways of interaction or synergy between these two states of immune dysregulation is lacking. This study therefore sought to elucidate mechanisms underlying the immune dysregulation observed during sepsis in the setting of chronic alcohol exposure. Using a murine model of chronic ethanol ingestion followed by sepsis induction via cecal ligation and puncture, we determined that while CD4+ and CD8+ T cells isolated from alcohol fed mice eventually expressed the same cellular activation markers (CD44, CD69, and CD43) and effector molecules (IFN-γ, TNF) as their water fed counterparts, there was an overall delay in the acquisition of these phenotypes. This early lag in T cell activation was associated with significantly reduced IL-2 production at a later timepoint in both the CD4+ and CD8+ T cell compartments in alcohol sepsis, as well as with a reduced accumulation of CD8dim activated effectors. Taken together, these data suggest that delayed T cell activation may result in qualitative differences in the immune response to sepsis in the setting of chronic alcohol ingestion.

Increased proliferation of late-born retinal progenitor cells by gestational lead exposure delays rod and bipolar cell differentiation.

Science.gov (United States)

Chaney, Shawnta Y; Mukherjee, Shradha; Giddabasappa, Anand; Rueda, Elda M; Hamilton, W Ryan; Johnson, Jerry E; Fox, Donald A

2016-01-01

Studies of neuronal development in the retina often examine the stages of proliferation, differentiation, and synaptic development, albeit independently. Our goal was to determine if a known neurotoxicant insult to a population of retinal progenitor cells (RPCs) would affect their eventual differentiation and synaptic development. To that end, we used our previously published human equivalent murine model of low-level gestational lead exposure (GLE). Children and animals with GLE exhibit increased scotopic electroretinogram a- and b-waves. Adult mice with GLE exhibit an increased number of late-born RPCs, a prolonged period of RPC proliferation, and an increased number of late-born rod photoreceptors and rod and cone bipolar cells (BCs), with no change in the number of late-born Müller glial cells or early-born neurons. The specific aims of this study were to determine whether increased and prolonged RPC proliferation alters the spatiotemporal differentiation and synaptic development of rods and BCs in early postnatal GLE retinas compared to control retinas. C57BL/6N mouse pups were exposed to lead acetate via drinking water throughout gestation and until postnatal day 10, which is equivalent to the human gestation period for retinal neurogenesis. RT-qPCR, immunohistochemical analysis, and western blots of well-characterized, cell-specific genes and proteins were performed at embryonic and early postnatal ages to assess rod and cone photoreceptor differentiation, rod and BC differentiation and synaptic development, and Müller glial cell differentiation. Real-time quantitative PCR (RT-qPCR) with the rod-specific transcription factors Nrl , Nr2e3 , and Crx and the rod-specific functional gene Rho , along with central retinal confocal studies with anti-recoverin and anti-rhodopsin antibodies, revealed a two-day delay in the differentiation of rod photoreceptors in GLE retinas. Rhodopsin immunoblots supported this conclusion. No changes in glutamine synthetase gene

Chikungunya virus–induced autophagy delays caspase-dependent cell death

Science.gov (United States)

Joubert, Pierre-Emmanuel; Werneke, Scott W.; de la Calle, Claire; Guivel-Benhassine, Florence; Giodini, Alessandra; Peduto, Lucie; Levine, Beth; Schwartz, Olivier; Lenschow, Deborah J.

2012-01-01

Autophagy is an important survival pathway and can participate in the host response to infection. Studying Chikungunya virus (CHIKV), the causative agent of a major epidemic in India, Southeast Asia, and southern Europe, we reveal a novel mechanism by which autophagy limits cell death and mortality after infection. We use biochemical studies and single cell multispectral assays to demonstrate that direct infection triggers both apoptosis and autophagy. CHIKV-induced autophagy is mediated by the independent induction of endoplasmic reticulum and oxidative stress pathways. These cellular responses delay apoptotic cell death by inducing the IRE1α–XBP-1 pathway in conjunction with ROS-mediated mTOR inhibition. Silencing of autophagy genes resulted in enhanced intrinsic and extrinsic apoptosis, favoring viral propagation in cultured cells. Providing in vivo evidence for the relevance of our findings, Atg16LHM mice, which display reduced levels of autophagy, exhibited increased lethality and showed a higher sensitivity to CHIKV-induced apoptosis. Based on kinetic studies and the observation that features of apoptosis and autophagy were mutually exclusive, we conclude that autophagy inhibits caspase-dependent cell death but is ultimately overwhelmed by viral replication. Our study suggests that inducers of autophagy may limit the pathogenesis of acute Chikungunya disease. PMID:22508836

Acute and delayed effect of (-) deprenyl and (-) 1-phenyl-2-propylaminopentane (PPAP) on the serotonin content of peritoneal cells (white blood cells and mast cells).

Science.gov (United States)

Csaba, G; Kovács, P; Pállinger, Eva

2006-01-01

Acute and delayed (hormonal imprinting) effect of (-) deprenyl and its derivative without MAO-B inhibitory activity (-) PPAP, were studied on cells of the peritoneal fluid (lymphocytes, monocytes, granulocytes and mast cells) by flow cytometric and confocal microscopic analysis. Thirty minutes after treatment of 6-week-old female animals, deprenyl was ineffective while PPAP significantly increased the serotonin level of these cells. Three weeks after treatment at weaning, deprenyl drastically decreased the serotonin level of each cell type, while PPAP moderately but significantly increased the serotonin level of monocytes, granulocytes and mast cells. This means that the two related molecules have different effects on the immune cells, which seem to be independent of MAO-B inhibition. The experiments emphasize the necessity of studying the prolonged effects of biologically active molecules, even if they are without acute effects. As serotonin is a modulator of the immune system, the influence on immune cells of the molecules studied can contribute to their enhancing effect. Copyright 2004 John Wiley & Sons, Ltd.

Staphylococcus aureus-induced G2/M phase transition delay in host epithelial cells increases bacterial infective efficiency.

Directory of Open Access Journals (Sweden)

Ludmila Alekseeva

Full Text Available Staphylococcus aureus is a highly versatile, opportunistic pathogen and the etiological agent of a wide range of infections in humans and warm-blooded animals. The epithelial surface is its principal site of colonization and infection. In this work, we investigated the cytopathic effect of S. aureus strains from human and animal origins and their ability to affect the host cell cycle in human HeLa and bovine MAC-T epithelial cell lines. S. aureus invasion slowed down cell proliferation and induced a cytopathic effect, resulting in the enlargement of host cells. A dramatic decrease in the number of mitotic cells was observed in the infected cultures. Flow cytometry analysis revealed an S. aureus-induced delay in the G2/M phase transition in synchronous HeLa cells. This delay required the presence of live S. aureus since the addition of the heat-killed bacteria did not alter the cell cycle. The results of Western blot experiments showed that the G2/M transition delay was associated with the accumulation of inactive cyclin-dependent kinase Cdk1, a key inducer of mitosis entry, and with the accumulation of unphosphorylated histone H3, which was correlated with a reduction of the mitotic cell number. Analysis of S. aureus proliferation in asynchronous, G1- and G2-phase-enriched HeLa cells showed that the G2 phase was preferential for bacterial infective efficiency, suggesting that the G2 phase delay may be used by S. aureus for propagation within the host. Taken together, our results divulge the potential of S. aureus in the subversion of key cellular processes such as cell cycle progression, and shed light on the biological significance of S. aureus-induced host cell cycle alteration.

Mitotic delay of irradiated cells and its connection with quantity of radiation injuries

International Nuclear Information System (INIS)

Lobachevskij, P.N.; Fominykh, E.V.

1989-01-01

The study is dedicated to development of mathematical approach to interpret radiation-induced mitosic delay. An assumption is made that mitotic delay is conditioned by discrete injuries distributed in cells according to stochasticity of interaction of radiation and target substance. It is supposed to consider the problem on injuries nature causing mitotic delay and to use the developed method for accounting the effect of radiation-induced mitotic delay on registered chromosomal aberration yield. 10 refs.; 2 figs.; 3 tabs

Action of caffeine on x-irradiated HeLa cells. IV. Progression delays and enhanced cell killing at high caffeine concentrations

International Nuclear Information System (INIS)

Tolmach, L.J.; Busse, P.M.

1980-01-01

The response of x-irradiated and unirradiated HeLa S3 cells to treatment with caffeine at concentrations between 1 and 10 nM has been examined with respect to both delay in progression through the cell generation cycle and enhancement of the expression of potentially lethal x-ray damage. Progression is delayed in a concentration-dependent fashion: the generation time is doubled at about 4 mM. The duration of G 1 is lengthened, and the rate of DNA synthesis is reduced, although the kinetics are different in the two phases; the rate of DNA synthesis is usually unaffected at 1 or 2 mM, while there is no concentration threshold for the slowing of progression through G 1 . Progression through G 2 appears to be unaffected by concentrations up to at least 10 mM. Killing of irradiated cells in G 2 is somewhat greater after treatment with the higher caffeine concentrations than reported previously for 1 mM. Moreover, an additional mode of killing is observed in irradiated G 1 cells which had been found previously to be only slightly affected by 1 mM caffeine; they suffer extensive killing at concentrations above 5 mM. The time-survival curves for irradiated, caffeine-treated G 1 and G 2 cells have characteristically different shapes. The dose-survival curves for cells treated with the higher caffeine concentrations display steeper terminal slopes and narrower shoulders

Enhancing endogenous stem cells in the newbornvia delayed umbilical cord clamping

Institute of Scientific and Technical Information of China (English)

Christopher Lawton; Sandra Acosta; Nate Watson; Chiara Gonzales-Portillo; hTeo Diamandis; Naoki Tajiri; Yuji Kaneko; Paul R. Sanberg; Cesar V. Borlongan

2015-01-01

There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal beneifts including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deifciency anemia in term infants. Human umbilical cord blood con-tains signiifcant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it en-hances blood lfow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant’s susceptibility to both neonatal and age-related diseases.

Chronic Alcohol Ingestion Delays T Cell Activation and Effector Function in Sepsis.

Directory of Open Access Journals (Sweden)

Lindsay M Margoles

Full Text Available Sepsis is the leading cause of death in intensive care units in the US, and it is known that chronic alcohol use is associated with higher incidence of sepsis, longer ICU stays, and higher mortality from sepsis. Both sepsis and chronic alcohol use are associated with immune deficits such as decreased lymphocyte numbers, impaired innate immunity, delayed-type hypersensitivity reactions, and susceptibility to infections; however, understanding of specific pathways of interaction or synergy between these two states of immune dysregulation is lacking. This study therefore sought to elucidate mechanisms underlying the immune dysregulation observed during sepsis in the setting of chronic alcohol exposure. Using a murine model of chronic ethanol ingestion followed by sepsis induction via cecal ligation and puncture, we determined that while CD4+ and CD8+ T cells isolated from alcohol fed mice eventually expressed the same cellular activation markers (CD44, CD69, and CD43 and effector molecules (IFN-γ, TNF as their water fed counterparts, there was an overall delay in the acquisition of these phenotypes. This early lag in T cell activation was associated with significantly reduced IL-2 production at a later timepoint in both the CD4+ and CD8+ T cell compartments in alcohol sepsis, as well as with a reduced accumulation of CD8dim activated effectors. Taken together, these data suggest that delayed T cell activation may result in qualitative differences in the immune response to sepsis in the setting of chronic alcohol ingestion.

Dynamics of an HBV/HCV infection model with intracellular delay and cell proliferation

Science.gov (United States)

Zhang, Fengqin; Li, Jianquan; Zheng, Chongwu; Wang, Lin

2017-01-01

A new mathematical model of hepatitis B/C virus (HBV/HCV) infection which incorporates the proliferation of healthy hepatocyte cells and the latent period of infected hepatocyte cells is proposed and studied. The dynamics is analyzed via Pontryagin's method and a newly proposed alternative geometric stability switch criterion. Sharp conditions ensuring stability of the infection persistent equilibrium are derived by applying Pontryagin's method. Using the intracellular delay as the bifurcation parameter and applying an alternative geometric stability switch criterion, we show that the HBV/HCV infection model undergoes stability switches. Furthermore, numerical simulations illustrate that the intracellular delay can induce complex dynamics such as persistence bubbles and chaos.

New Therapeutic Approaches to Prevent or Delay Beta-Cell Failure in Diabetes

Directory of Open Access Journals (Sweden)

Ionica Floriana Elvira

2015-09-01

Full Text Available Background and aims: The most recent estimates of International Diabetes Federation indicate that 382 million people have diabetes, and the incidence of this disease is increasing. While in type 1 diabetes mellitus (T1DM beta-cell death is autoimmunemediated, type 2 diabetes mellitus (T2DM results from an interaction between genetic and environmental factors that impair beta-cell function and insulin action. Many people with T2DM remain unaware of their illness for a long time because symptoms may take years to appear or be recognized, while the body is affected by excess blood glucose. These patients are often diagnosed only when diabetes complications have already developed. The aim of this article was to perform a review based on literature data on therapeutic modalities to prevent/delay beta cell function decline. Material and Methods: We searched MEDLINE from 2000 to the present to identify the therapeutic approaches to prevent or delay beta-cell failure in patients with T2DM. Results and conclusions: Several common polymorphisms in genes linked to monogenic forms of diabetes appear to influence the response to T2DM pharmacotherapy. Recent studies report the role of the G protein coupled receptor 40 (GPR40, also known as Free Fatty Acids Receptor 1 (FFAR1 in the regulation of beta-cell function- CNX-011-67 (a GPR40 agonist has the potential to provide good and durable glycemic control in T2DM patients.

Silent Crooke’s cell corticotroph adenoma of the pituitary gland presenting as delayed puberty

Directory of Open Access Journals (Sweden)

Dinesh Giri

2017-03-01

Full Text Available Corticotroph adenomas are extremely rare in children and adolescents. We present a 15-year-old boy who was investigated for delayed puberty (A1P2G1, bilateral testicular volumes of 3 mL each. There was no clinical or laboratory evidence suggestive of chronic illness, and the initial clinical impression was constitutional delay in puberty. Subsequently, MRI scan of the brain revealed the presence of a mixed cystic and solid pituitary lesion slightly displacing the optic chiasma. The lesion was removed by transphenoidal surgery and the biopsy confirmed the lesion to be pituitary adenoma. Furthermore, the adenoma cells also had Crooke’s hyaline changes and were intensely positive for ACTH. However there was no clinical/biochemical evidence of ACTH excess. There was a spontaneous pubertal progression twelve months after the surgery (A2P4G4, with bilateral testicular volume of 8 mL. Crooke’s cell adenoma is an extremely rare and aggressive variant of corticotroph adenoma that can uncommonly present as a silent corticotroph adenoma in adults. We report for the first time Crooke’s cell adenoma in an adolescent boy presenting with delayed puberty.

FREQUENCY CATASTROPHE AND CO-EXISTING ATTRACTORS IN A CELL Ca2+ NONLINEAR OSCILLATION MODEL WITH TIME DELAY*

Institute of Scientific and Technical Information of China (English)

应阳君; 黄祖洽

2001-01-01

Frequency catastrophe is found in a cell Ca2+ nonlinear oscillation model with time delay. The relation of the frequency transition to the time delay is studied by numerical simulations and theoretical analysis. There is a range of parameters in which two kinds of attractors with great frequency differences co-exist in the system. Along with parameter changes, a critical phenomenon occurs and the oscillation frequency changes greatly. This mechanism helps us to deepen the understanding of the complex dynamics of delay systems, and might be of some meaning in cell signalling.

CALCULUS FROM THE PAST: MULTIPLE DELAY SYSTEMS ARISING IN CANCER CELL MODELLING

KAUST Repository

WAKE, G. C.; BYRNE, H. M.

2013-01-01

Nonlocal calculus is often overlooked in the mathematics curriculum. In this paper we present an interesting new class of nonlocal problems that arise from modelling the growth and division of cells, especially cancer cells, as they progress through the cell cycle. The cellular biomass is assumed to be unstructured in size or position, and its evolution governed by a time-dependent system of ordinary differential equations with multiple time delays. The system is linear and taken to be autonomous. As a result, it is possible to reduce its solution to that of a nonlinear matrix eigenvalue problem. This method is illustrated by considering case studies, including a model of the cell cycle developed recently by Simms, Bean and Koeber. The paper concludes by explaining how asymptotic expressions for the distribution of cells across the compartments can be determined and used to assess the impact of different chemotherapeutic agents. Copyright © 2013 Australian Mathematical Society.

Modelling radiation-induced cell death and tumour re-oxygenation: local versus global and instant versus delayed cell death

International Nuclear Information System (INIS)

Gago-Arias, Araceli; Espinoza, Ignacio; Sánchez-Nieto, Beatriz; Aguiar, Pablo; Pardo-Montero, Juan

2016-01-01

The resistance of hypoxic cells to radiation, due to the oxygen dependence of radiosensitivity, is well known and must be taken into account to accurately calculate the radiation induced cell death. A proper modelling of the response of tumours to radiation requires deriving the distribution of oxygen at a microscopic scale. This usually involves solving the reaction-diffusion equation in tumour voxels using a vascularization distribution model. Moreover, re-oxygenation arises during the course of radiotherapy, one reason being the increase of available oxygen caused by cell killing, which can turn hypoxic tumours into oxic. In this work we study the effect of cell death kinetics in tumour oxygenation modelling, analysing how it affects the timing of re-oxygenation, surviving fraction and tumour control. Two models of cell death are compared, an instantaneous cell killing, mimicking early apoptosis, and a delayed cell death scenario in which cells can die shortly after being damaged, as well as long after irradiation. For each of these scenarios, the decrease in oxygen consumption due to cell death can be computed globally (macroscopic voxel average) or locally (microscopic). A re-oxygenation model already used in the literature, the so called full re-oxygenation, is also considered. The impact of cell death kinetics and re-oxygenation on tumour responses is illustrated for two radiotherapy fractionation schemes: a conventional schedule, and a hypofractionated treatment. The results show large differences in the doses needed to achieve 50% tumour control for the investigated cell death models. Moreover, the models affect the tumour responses differently depending on the treatment schedule. This corroborates the complex nature of re-oxygenation, showing the need to take into account the kinetics of cell death in radiation response models. (paper)

Enhancing endogenous stem cells in the newborn via delayed umbilical cord clamping

Directory of Open Access Journals (Sweden)

Christopher Lawton

2015-01-01

Full Text Available There is currently no consensus among clinicians and scientists over the appropriate or optimal timing for umbilical cord clamping. However, many clinical studies have suggested that delayed cord clamping is associated with various neonatal benefits including increased blood volume, reduced need for blood transfusion, increased cerebral oxygenation in pre-term infants, and decreased frequency of iron deficiency anemia in term infants. Human umbilical cord blood contains significant amounts of stem and progenitor cells and is currently used in the treatment of several life-threatening diseases. We propose that delayed cord clamping be encouraged as it enhances blood flow from the placenta to the neonate, which is accompanied by an increase supply of valuable stem and progenitor cells, as well as may improve blood oxygenation and increase blood volume, altogether reducing the infant′s susceptibility to both neonatal and age-related diseases.

The relationship between cell killing, chromosome aberrations, spindle defects, and mitotic delay in mouse lymphoma cells of differential sensitivity to X-rays

International Nuclear Information System (INIS)

Scott, D.; Zampetti-Bosseler, F.

1980-01-01

A study has been made of the effects of x radiation on an ultrasensitive subline of L5178Y mouse lymphoma cells. It has been shown that at survival levels above about 20 per cent, chromosome structural aberrations which lead to bridges and fragments at anaphase are about four times more frequent than spindle defects. The results demonstrated the higher frequency of structural aberrations and spindle defects, and the greater mitotic delay in the X-ray-sensitive than in the X-ray-resistant cell line. A model is proposed which causally relates these end-points to cell killing and DNA repair. (author)

De novo alloreactive memory CD8+ T cells develop following allogeneic challenge when CNI immunosuppression is delayed.

Science.gov (United States)

Hart-Matyas, M; Gareau, A J; Hirsch, G M; Lee, T D G

2015-01-01

Allospecific memory T cells are a recognized threat to the maintenance of solid-organ transplants. Limited information exists regarding the development of alloreactive memory T cells when post-transplant immunosuppression is present. The clinical practice of delaying calcineurin inhibitor (CNI) initiation post-transplant may permit the development of a de novo allospecific memory population. We investigated the development of de novo allospecific memory CD8+ T cells following the introduction of CNI immunosuppression in a murine model using allogeneic cell priming. Recipient mice alloprimed with splenocytes from fully mismatched donors received cyclosporine (CyA), initiated at 0, 2, 6, or 10days post-prime. Splenocytes from recipients were analyzed by flow cytometry or enzyme-linked immunosorbent assay for evidence of memory cell formation. Memory and effector CD8+ T cell development was prevented when CyA was initiated at 0day or 2days post-prime (p0.05). Delaying CyA up to 6days or later post-prime permits the development of functional de novo allospecific memory CD8+ T cells. The development of this potentially detrimental T cell population in patients could be prevented by starting CNI immunosuppression early post-transplant. Copyright © 2014 Elsevier B.V. All rights reserved.

Coliphage 186 replication is delayed when the host cell is UV irradiated before infection

International Nuclear Information System (INIS)

Hooper, I.; Woods, W.H.; Egan, B.

1981-01-01

In contrast to results with injections by lambda and P2, the latent period for infection by coliphage 186 is extended when the host cell is UV irradiated before infection. We find that 186 replication is significantly delayed in such a cell, even though the phage itself has not been irradiated. In contrast, replication of the closely related phage P2 under the same conditions is not affected

Delay equations modeling the effects of phase-specific drugs and immunotherapy on proliferating tumor cells.

Science.gov (United States)

Barbarossa, Maria Vittoria; Kuttler, Christina; Zinsl, Jonathan

2012-04-01

In this work we present a mathematical model for tumor growth based on the biology of the cell cycle. For an appropriate description of the effects of phase-specific drugs, it is necessary to look at the cell cycle and its phases. Our model reproduces the dynamics of three different tumor cell populations: quiescent cells, cells during the interphase and mitotic cells. Starting from a partial differential equations (PDEs) setting, a delay differential equations (DDE) model is derived for an easier and more realistic approach. Our equations also include interactions of tumor cells with immune system effectors. We investigate the model both from the analytical and the numerical point of view, give conditions for positivity of solutions and focus on the stability of the cancer-free equilibrium. Different immunotherapeutic strategies and their effects on the tumor growth are considered, as well.

Delayed expression of apoptosis in X-irradiated human leukemic MOLT-4 cells transfected with mutant p53

International Nuclear Information System (INIS)

Nakano, Hisako; Yonekawa, Hiromichi; Shinohara, Kunio

2003-01-01

The effects of X-rays on cell survival, apoptosis, and long-term response in the development of cell death as measured by the dye exclusion test were studied in human leukemic MOLT-4 cells (p53 wild-type) stably transfected with a mutant p53 cDNA expression vector. Cell survival, as determined from colony-forming ability, was increased in an expression level dependent manner, but the increase was partial even with the highest-expressing clone (B3). This contrasts with the prior observation that cell death and apoptosis in B3 are completely inhibited at 24 h after irradiation with 1.8 Gy of X-rays. The examination of B3 cells incubated for longer than 24 h after X-irradiation showed a delay in the induction of cell death and apoptosis. Western blot analysis revealed that the time required to reach the highest level of wild-type p53 protein in B3 was longer than the time in MOLT-4 and that the p53 may be stabilized by the phosphorylation at Ser-15. These results suggest that the introduction of mutant p53 into MOLT-4 merely delays the development of apoptosis, during which the cells could repair the damage induced by X-rays, and results in the partial increase in cell survival. (author)

Lithium delays the radiation-induced apoptotic process in external granule cells of mouse cerebellum

International Nuclear Information System (INIS)

Inouye, Minoru; Yamamura, Hideki; Nakano, Atsuhiro.

1995-01-01

Proliferating cells of the external granular layer (EGL) in the developing cerebellum are highly sensitive to ionizing radiation. We examined the effect of lithium, an inhibitor of intracellular signaling, on the manifestation of radiation-induced apoptosis. Newborn mice were exposed to 0.5 Gy gamma-irradiation alone, or first were treated with lithium (10 μmol/g, SC) then given 0.5 Gy irradiation 2 hr later. The EGL was examined histologically for apoptosis at various times after treatment. Apoptotic cells increased rapidly, peaked (about 14%) 6 hr after irradiation, then decreased gradually to the control level by 24 hr. Prior treatment with lithium delayed the manifestation of apoptosis, the peak appearing at 12 hr. The disappearance of dead cells was delayed for about one day. The lithium concentration in the whole brain increased rapidly, being 30 μg/g at the time of irradiation and remaining at more than 40 μg/g for 40 hr. Lithium is reported to inhibit guanine-nucleotide binding to G proteins as well as phosphoinositide turnover. Of the variety of lesions induced by radiation, DNA double strand breaks are the most important source of cell lethality. The present findings, however, suggest that cyclic AMP-mediated and/or phosphoinositide-mediated signaling systems regulate radiation-induced apoptosis. (author)

Lithium delays the radiation-induced apoptotic process in external granule cells of mouse cerebellum.

Science.gov (United States)

Inouye, M; Yamamura, H; Nakano, A

1995-09-01

Proliferating cells of the external granular layer (EGL) in the developing cerebellum are highly sensitive to ionizing radiation. We examined the effect of lithium, an inhibitor of intracellular signaling, on the manifestation of radiation-induced apoptosis. Newborn mice were exposed to 0.5 Gy gamma-irradiation alone, or first were treated with lithium (10 mumol/g, SC) then given 0.5 Gy irradiation 2 hr later. The EGL was examined histologically for apoptosis at various times after treatment. Apoptotic cells increased rapidly, peaked (about 14%) 6 hr after irradiation, then decreased gradually to the control level by 24 hr. Prior treatment with lithium delayed the manifestation of apoptosis, the peak appearing at 12 hr. The disappearance of dead cells was delayed for about one day. The lithium concentration in the whole brain increased rapidly, being 30 micrograms/g at the time of irradiation and remaining at more than 40 micrograms/g for 40 hr. Lithium is reported to inhibit guanine-nucleotide binding to G proteins as well as phosphoinositide turnover. Of the variety of lesions induced by radiation, DNA double strand breaks are the most important source of cell lethality. The present findings, however, suggest that cyclic AMP-mediated and/or phosphoinositidemediated signaling systems regulate radiation-induced apoptosis.

Lithium delays the radiation-induced apoptotic process in external granule cells of mouse cerebellum

Energy Technology Data Exchange (ETDEWEB)

Inouye, Minoru; Yamamura, Hideki [Nagoya Univ. (Japan). Research Inst. of Environmental Medicine; Nakano, Atsuhiro

1995-09-01

Proliferating cells of the external granular layer (EGL) in the developing cerebellum are highly sensitive to ionizing radiation. We examined the effect of lithium, an inhibitor of intracellular signaling, on the manifestation of radiation-induced apoptosis. Newborn mice were exposed to 0.5 Gy gamma-irradiation alone, or first were treated with lithium (10 {mu}mol/g, SC) then given 0.5 Gy irradiation 2 hr later. The EGL was examined histologically for apoptosis at various times after treatment. Apoptotic cells increased rapidly, peaked (about 14%) 6 hr after irradiation, then decreased gradually to the control level by 24 hr. Prior treatment with lithium delayed the manifestation of apoptosis, the peak appearing at 12 hr. The disappearance of dead cells was delayed for about one day. The lithium concentration in the whole brain increased rapidly, being 30 {mu}g/g at the time of irradiation and remaining at more than 40 {mu}g/g for 40 hr. Lithium is reported to inhibit guanine-nucleotide binding to G proteins as well as phosphoinositide turnover. Of the variety of lesions induced by radiation, DNA double strand breaks are the most important source of cell lethality. The present findings, however, suggest that cyclic AMP-mediated and/or phosphoinositide-mediated signaling systems regulate radiation-induced apoptosis. (author).

All delays before radiotherapy risk progression of Merkel cell carcinoma

International Nuclear Information System (INIS)

Tsang, G.; O'Brien, P.; Robertson, R.; Hamilton, C.; Wratten, C.; Denham, J.

2004-01-01

Prolonged waiting times for radiotherapy have resulted in many centres assigning priorities to various patient or diagnostic groups. A high risk of progression on a waiting list is one factor that would reasonably influence the priority. The present descriptive study of 27 patients with Merkel cell carcinoma (MCC) found that a median wait of 24 days for radiotherapy is associated with a high risk of progression. Eleven (41%) of 27 patients developed progressive disease, including five (45%) of 11 patients waiting for adjuvant radiotherapy. Patients treated adjuvantly also had longer waiting times prior to their initial radiotherapy consultation (median 41 days), which may have contributed to the rate of progression. Merkel cell carcinoma is an aggressive but curable malignancy and appropriate management should include efforts to minimize all potential delays prior to the commencement of radiotherapy. Copyright (2004) Blackwell Science Pty Ltd

Inhibition of phosphatidylinositol 3-kinase promotes tumor cell resistance to chemotherapeutic agents via a mechanism involving delay in cell cycle progression

International Nuclear Information System (INIS)

McDonald, Gail T.; Sullivan, Richard; Pare, Genevieve C.; Graham, Charles H.

2010-01-01

Approaches to overcome chemoresistance in cancer cells have involved targeting specific signaling pathways such as the phosphatidylinositol 3-kinase (PI3K) pathway, a stress response pathway known to be involved in the regulation of cell survival, apoptosis and growth. The present study determined the effect of PI3K inhibition on the clonogenic survival of human cancer cells following exposure to various chemotherapeutic agents. Treatment with the PI3K inhibitors LY294002 or Compound 15e resulted in increased survival of MDA-MB-231 breast carcinoma cells after exposure to doxorubicin, etoposide, 5-fluorouracil, and vincristine. Increased survival following PI3K inhibition was also observed in DU-145 prostate, HCT-116 colon and A-549 lung carcinoma cell lines exposed to doxorubicin. Increased cell survival mediated by LY294002 was correlated with a decrease in cell proliferation, which was linked to an increase in the proportion of cells in the G 1 phase of the cell cycle. Inhibition of PI3K signaling also resulted in higher levels of the cyclin-dependent kinase inhibitors p21 Waf1/Cip1 and p27 Kip1 ; and knockdown of p27 kip1 with siRNA attenuated resistance to doxorubicin in cells treated with LY294002. Incubation in the presence of LY294002 after exposure to doxorubicin resulted in decreased cell survival. These findings provide evidence that PI3K inhibition leads to chemoresistance in human cancer cells by causing a delay in cell cycle; however, the timing of PI3K inhibition (either before or after exposure to anti-cancer agents) may be a critical determinant of chemosensitivity.

Vitamin E analogue, D-alpha tocopherol succinate, enhances x-ray induced growth delay of human adenocarcinoma cancer cell line

International Nuclear Information System (INIS)

Jaworska, A.; Ottesen, T.E.

2003-01-01

The purpose of this study was to assess the effects of d-alpha Tocopherol succinate (alpha-TS) in modifying radiation-induced viability reduction and apoptosis occurrence in the model for normal and cancer cells. Our hypothesis was that alpha-TS enhances the growth-inhibitory effect of x-irradiation in cancer cells and that the effect is more pronounced in these cells than in normal cells. Murine NIH 3T3 Swiss albino embryonic cells and HT29 human Caucasian colon adenocarcinoma cells were used in the experiments. Alpha-TS was added to the cultures 1 h prior to irradiation with doses of 2 or 5Gy of x-ray. After irradiation cells were incubated for 73 h. Trypan blue exclusion viability test and estimation of apoptosis and necrosis were made. Apoptotic and necrotic cells were counted in fluorescence microscope using fluorescence dyes: propidium iodide and Hoechst 33342. For experiments with the dose of 5 Gy at least five series of experiments were performed. At lower doses (up to approximately 25μM/ml) treatment with alpha-TS alone enhanced growth of both cell lines. At higher doses treatment with alpha-TS alone delayed the growth of the cell cultures, accompanied by 20-25% necrosis. At the concentrations higher than 25μM/mL alpha-TS alone caused growth delay of both cell cultures, being much more pronounced for the cancer cell line HT29. At the concentrations of 50 μM/mL, responsible for about 30-60% of growth delay, there was observed a synergy effect for x-rays and alpha-TS for both cell lines. The effect was more pronounced for HT29 cells (DMF=0.48 for HT29 versus DMF=0.73 for NIH 3T3). These results may confirm the views of the literature reports suggesting that use of vitamin E together with radiation could be favorable for colon cancer treatment; however, more experiments using more advanced techniques are needed

Nicotinamide phosphoribosyltransferase delays cellular senescence by upregulating SIRT1 activity and antioxidant gene expression in mouse cells.

Science.gov (United States)

Khaidizar, Fiqri D; Nakahata, Yasukazu; Kume, Akira; Sumizawa, Kyosuke; Kohno, Kenji; Matsui, Takaaki; Bessho, Yasumasa

2017-12-01

Senescent cells accumulate in tissues of aged animals and deteriorate tissue functions. The elimination of senescent cells from aged mice not only attenuates progression of already established age-related disorders, but also extends median lifespan. Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in mammalian NAD + salvage pathway, has shown a protective effect on cellular senescence of human primary cells. However, it still remains unclear how NAMPT has a protective impact on aging in vitro and in vivo. In this study, we found that primary mouse embryonic fibroblast (MEF) cells undergo progressive decline of NAMPT and NAD + contents during serial passaging before becoming senescent. Furthermore, we showed that constitutive Nampt over-expression increases cellular NAD + content and delays cellular senescence of MEF cells in vitro. We further found that constitutive Nampt over-expression increases SIRT1 activity, increases the expression of antioxidant genes, superoxide dismutase 2 and catalase and promotes resistance against oxidative stress. These findings suggest that Nampt over-expression in MEF cells delays cellular senescence by the mitigation of oxidative stress via the upregulation of superoxide dismutase 2 and catalase gene expressions by SIRT1 activation. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

Action of caffeine on x-irradiated HeLa cells. I. Delayed inhibition of DNA synthesis

International Nuclear Information System (INIS)

Tolmach, L.J.; Jones, R.W.; Busse, P.M.

1977-01-01

Treatment of HeLa S3 cells with 1 mM caffeine delays progression through G1 by 1.5 hours but causes no other detectable inhibition of cell progression; it sometimes results in a large stimulation of thymidine incorporation. When this concentration is applied to cells that have been irradiated with 1-krad doses of 220-kV x rays, there is a marked suppression of both the inhibition of DNA synthesis and G2 arrest induced by the radiation. Larger doses require higher concentrations of caffeine to suppress the inhibition of DNA synthesis. Delaying addition until the rate of synthesis is at its minimum (1.5 hours after irradiation with 1 krad) results in a slightly accelerated recovery of the rate. Treatment before or during irradiation is without effect on the inhibition. Removal of the caffeine as late as 6 hours after its addition at the time of irradiation results in a prompt inhibition in DNA synthesis that mimics that observed immediately after irradiation in the absence of caffeine. These findings raise the possibility that the depression in rate of DNA systhesis might not result from radiation damage introduced into the replicon initiation system, but rather may be an indirect consequence of damage residing elsewhere in the irradiated cell

A digital TDC with a reduced number of delay line cells

International Nuclear Information System (INIS)

Boujrad, A.; Bloyet, D.; Tripon, M.

2002-01-01

In nuclear physics experiments, a decision maker named as 'trigger' gives a bit pattern which allows the fired detectors identification. As the data acquisition dead time is greater than the time between physical events, timing information is essential. We add to the trigger function a Time to Digital Converter (TDC) in order to make a separation between events. The paper describes the architecture chosen for the TDC and illustrates the contribution of each element to the TDC performance. An eight-bit counter is used for the dynamic range of the TDC (in microsecond) associated to a delay line improving the resolution (in nanosecond). The study shows that exploiting the two system clock states (high and low) allows to reduce the number of delay line cells. The Differential Nonlinearity Measurements are given for different resolutions (1, 2 and 5 ns) and illustrate the clock period, the clock duty cycle and the delay line contributions to the TDC performances

Ectopic expression of Capsicum-specific cell wall protein Capsicum annuum senescence-delaying 1 (CaSD1) delays senescence and induces trichome formation in Nicotiana benthamiana.

Science.gov (United States)

Seo, Eunyoung; Yeom, Seon-In; Jo, Sunghwan; Jeong, Heejin; Kang, Byoung-Cheorl; Choi, Doil

2012-04-01

Secreted proteins are known to have multiple roles in plant development, metabolism, and stress response. In a previous study to understand the roles of secreted proteins, Capsicum annuum secreted proteins (CaS) were isolated by yeast secretion trap. Among the secreted proteins, we further characterized Capsicum annuum senescence-delaying 1 (CaSD1), a gene encoding a novel secreted protein that is present only in the genus Capsicum. The deduced CaSD1 contains multiple repeats of the amino acid sequence KPPIHNHKPTDYDRS. Interestingly, the number of repeats varied among cultivars and species in the Capsicum genus. CaSD1 is constitutively expressed in roots, and Agrobacterium-mediated transient overexpression of CaSD1 in Nicotiana benthamiana leaves resulted in delayed senescence with a dramatically increased number of trichomes and enlarged epidermal cells. Furthermore, senescence- and cell division-related genes were differentially regulated by CaSD1-overexpressing plants. These observations imply that the pepper-specific cell wall protein CaSD1 plays roles in plant growth and development by regulating cell division and differentiation.

Human umbilical cord blood mononuclear cell transplantation for delayed encephalopathy after carbon monoxide intoxication

Directory of Open Access Journals (Sweden)

Gong D

2013-08-01

Full Text Available Dianrong Gong,1 Haiyan Yu,1 Weihua Wang,2 Haixin Yang,1 Fabin Han1,21Department of Neurology, 2Centre for Stem Cells and Regenerative Medicine, Liaocheng People's Hospital, The Affiliated Liaocheng Hospital, Taishan Medical University, Shandong, People's Republic of ChinaAbstract: Stem cell transplantation is one of the potential treatments for neurological disorders. Since human umbilical cord stem cells have been shown to provide neuroprotection and promote neural regeneration, we have attempted to transplant the human umbilical cord blood mononuclear cells (hUCB-MNCs to treat patients with delayed encephalopathy after carbon monoxide intoxication (DEACOI. The hUCB-MNCs were isolated from fresh umbilical cord blood and were given to patients subarachnoidally. Physical examinations, mini-mental state examination scores, and computed tomography scans were used to evaluate the improvement of symptoms, signs, and pathological changes of the patient's brain before and after hUCB-MNC transplantation. A total of 12 patients with DEACOI were treated with hUCB-MNCs in this study. We found that most of the patients have shown significant improvements in movement, behavior, and cognitive function, and improved brain images in 1–4 months from the first transplantation of hUCB-MNCs. None of these patients have been observed to have any severe adverse effects. Our study suggests that the hUCB-MNC transplantation may be a safe and effective treatment for DEACOI. Further studies and clinical trials with more cases, using more systematic scoring methods, are needed to evaluate brain structural and functional improvements in patients with DEACOI after hUCB-MNC therapy.Keywords: human umbilical cord blood mononuclear cells, transplantation, delayed encephalopathy after carbon monoxide intoxication, MMSE

Radiobiological properties of radiosensitive XR-1 Chinese hamster cells and hybrids from these and human A-T cells

International Nuclear Information System (INIS)

Bahari, I.B.

1989-01-01

Results indicate that XR-1 cells were very radiosensitive to gamma-irradiation compared to its parental type, and that this radiosensitivity is cell cycle dependent. Irradiating the cells the G 1 or plateau phase did not induce any delay entering S-phase but mitotic delays were observed in both XR-1 and the wild-type cells. The delays per unit dose were much longer for XR-1. A delay in subculture from plateau phase reduced the mitotic delay in both cell lines. Unlike the wild-type cells which expressed virtually all chromosome-type aberrations after irradiation of G 1 cells, the XR-1 cells expressed both chromatid- as well as chromosome-type aberrations. There was a one-to-one correlation between total aberrations induced and lethality for both cells. Many of these radiobiological properties of XR-1 cells relative to the wild-type cells, mimic the response of A-T cells relative to the normal human cells. However, the restoration of radioresistance and cytogenetic response in the XR1/AT5BI(4) hybrid cells suggest that the XR-1 and A-T cells have different defects because of the complementation in the hybrids. It also appears that this genetic defect is recessive in nature

Expression of orphan G-protein coupled receptor GPR174 in CHO cells induced morphological changes and proliferation delay via increasing intracellular cAMP

Energy Technology Data Exchange (ETDEWEB)

Sugita, Kazuya; Yamamura, Chiaki; Tabata, Ken-ichi [Laboratory of Pharmacoinformatics, Graduate School of Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan); Fujita, Norihisa, E-mail: nori@ph.ritsumei.ac.jp [Laboratory of Pharmacoinformatics, Graduate School of Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan); School of Pharmacy, Ristumeikan University, Kusatsu, Shiga 525-8577 (Japan)

2013-01-04

Highlights: Black-Right-Pointing-Pointer Expression of GPR174 in CHO cells induces morphological changes and proliferation delay. Black-Right-Pointing-Pointer These are due to increase in intracellular cAMP concentration. Black-Right-Pointing-Pointer Lysophosphatidylserine was identified to stimulate GPR174 leading to activate ACase. Black-Right-Pointing-Pointer The potencies of fatty acid moiety on LysoPS were oleoyl Greater-Than-Or-Slanted-Equal-To stearoyl > palmitoyl. Black-Right-Pointing-Pointer We propose that GPR174 is a lysophosphatidylserine receptor. -- Abstract: We established cell lines that stably express orphan GPCR GPR174 using CHO cells, and studied physiological and pharmacological features of the receptor. GPR174-expressing cells showed cell-cell adhesion with localization of actin filaments to cell membrane, and revealed significant delay of cell proliferation. Since the morphological changes of GPR174-cells were very similar to mock CHO cells treated with cholera toxin, we measured the concentration of intracellular cAMP. The results showed the concentration was significantly elevated in GPR174-cells. By measuring intracellular cAMP concentration in GPR174-cells, we screened lipids and nucleotides to identify ligands for GPR174. We found that lysophosphatidylserine (LysoPS) stimulated increase in intracellular cAMP in a dose-dependent manner. Moreover, phosphorylation of Erk was elevated by LysoPS in GPR174 cells. These LysoPS responses were inhibited by NF449, an inhibitor of G{alpha}{sub s} protein. These results suggested that GPR174 was a putative LysoPS receptor conjugating with G{alpha}{sub s}, and its expression induced morphological changes in CHO cells by constitutively activating adenylyl cycles accompanied with cell conjunctions and delay of proliferation.

Suppression of postmitochondrial signaling and delayed response to UV-induced nuclear apoptosis in HeLa cells

International Nuclear Information System (INIS)

Sasai, Kaori; Yajima, Hirohiko; Suzuki, Fumio

2002-01-01

Activation of postmitochondrial pathways by UV irradiation was examined using mouse lymphoma 3SB and human leukemic Jurkat cells and two human carcinoma cell lines (HeLa and MCF-7). Exposure of 3SB and Jurkat cells resulted in large amounts of cytochrome c and apoptosis-inducing factor (AIF) being released into the cytosol, and a clear laddering pattern of DNA fragments was observed within 3 h of incubation after irradiation. Simultaneously, activation of caspase-9 and its downstream caspases was detected. HeLa and MCF-7 cells also showed extensive release of mitochondrial factors and caspase-9 activation at 4 to 6 h after exposure, but apoptotic nuclear changes appeared much later. Compared with 3SB and Jurkat cells, these carcinoma cell lines exhibited reduced activation of caspase-9-like proteolytic activity by UV radiation, and levels of caspase-3-like activity in HeLa cells were extremely low, similar to those in caspase-3-deficient MCF-7 cells. These results suggest that the delayed response to UV-induced nuclear apoptosis in HeLa cells is due to a reduced activation of the caspase cascade downstream of cytochrome c release and suppression of caspase-3 activity. (author)

Analysis of X-ray induced cell-cycle perturbations in mouse osteosarcoma cells: a two-signal cell-cycle model

International Nuclear Information System (INIS)

Meeteren, A. van; Wijk, R. van; Stap, J.; Deys, B.F.

1984-01-01

The effects of X-irradiation on mouse osteosarcoma cells have been studied by time-lapse cinematography and the resulting pedigrees have been analysed statistically. It is shown that the irradiation treatment causes three types of cell kinetic lesions: cell death (disintegration), cell sterilization (failure to divide) and proliferation delay. The first two lesions are the most important with regard to survival of the irradiated cell in a clonal assay. Of these two lesions, sterilization appears to be highly correlated for sister cells, while this is not true for cell disintegration. This indicates that cell survival in a clonal assay may be a function of the ratio of the incidences of these two types of lesions. The X-ray-induced proliferation delay was studied in terms of intermitotic time distributions, mother-daughter correlation and sibling correlation in relation to the current cell-cycle phase at the time of treatment. This analysis shows that the effects of irradiation on these cell-cycle characteristics is highly cell-cycle-dependent. A qualitative model to account for the observations is presented. (author)

Analysis of X-ray induced cell-cycle perturbations in mouse osteosarcoma cells: a two-signal cell-cycle model

Energy Technology Data Exchange (ETDEWEB)

Meeteren, A van; Wijk, R van [Rijksuniversiteit Utrecht (Netherlands); Stap, J; Deys, B F [Amsterdam Univ. (Netherlands)

1984-03-01

The effects of X-irradiation on mouse osteosarcoma cells have been studied by time-lapse cinematography and the resulting pedigrees have been analysed statistically. It is shown that the irradiation treatment causes three types of cell kinetic lesions: cell death (disintegration), cell sterilization (failure to divide) and proliferation delay. The first two lesions are the most important with regard to survival of the irradiated cell in a clonal assay. Of these two lesions, sterilization appears to be highly correlated for sister cells, while this is not true for cell disintegration. This indicates that cell survival in a clonal assay may be a function of the ratio of the incidences of these two types of lesions. The X-ray-induced proliferation delay was studied in terms of intermitotic time distributions, mother-daughter correlation and sibling correlation in relation to the current cell-cycle phase at the time of treatment. This analysis shows that the effects of irradiation on these cell-cycle characteristics is highly cell-cycle-dependent. A qualitative model to account for the observations is presented.

Delayed rectifier K channels contribute to contrast adaptation in mammalian retinal ganglion cells

Science.gov (United States)

Weick, Michael; Demb, Jonathan B.

2011-01-01

SUMMARY Retinal ganglion cells adapt by reducing their sensitivity during periods of high contrast. Contrast adaptation in the firing response depends on both presynaptic and intrinsic mechanisms. Here, we investigated intrinsic mechanisms for contrast adaptation in OFF Alpha ganglion cells in the in vitro guinea pig retina. Using either visual stimulation or current injection, we show that brief depolarization evoked spiking and suppressed firing during subsequent depolarization. The suppression could be explained by Na channel inactivation, as shown in salamander cells. However, brief hyperpolarization in the physiological range (5–10 mV) also suppressed firing during subsequent depolarization. This suppression was sensitive selectively to blockers of delayed-rectifier K channels (KDR). Somatic membrane patches showed TEA-sensitive KDR currents with activation near −25 mV and removal of inactivation at voltages negative to Vrest. Brief periods of hyperpolarization apparently remove KDR inactivation and thereby increase the channel pool available to suppress excitability during subsequent depolarization. PMID:21745646

Stability and Hopf bifurcation in a delayed model for HIV infection of CD4{sup +}T cells

Energy Technology Data Exchange (ETDEWEB)

Cai Liming [Department of Mathematics, Xinyang Normal University, Xinyang, 464000 Henan (China); Beijing Institute of Information Control, Beijing 100037 (China)], E-mail: lmcai06@yahoo.com.cn; Li Xuezhi [Department of Mathematics, Xinyang Normal University, Xinyang, 464000 Henan (China)

2009-10-15

In this paper, we consider a delayed mathematical model for the interactions of HIV infection and CD4{sup +}T cells. We first investigate the existence and stability of the Equilibria. We then study the effect of the time delay on the stability of the infected equilibrium. Criteria are given to ensure that the infected equilibrium is asymptotically stable for all delay. Moreover, by applying Nyquist criterion, the length of delay is estimated for which stability continues to hold. Finally by using a delay {tau} as a bifurcation parameter, the existence of Hopf bifurcation is also investigated. Numerical simulations are presented to illustrate the analytical results.

Inhibition of DEPDC1A, a bad prognostic marker in multiple myeloma, delays growth and induces mature plasma cell markers in malignant plasma cells.

Directory of Open Access Journals (Sweden)

Alboukadel Kassambara

Full Text Available High throughput DNA microarray has made it possible to outline genes whose expression in malignant plasma cells is associated with short overall survival of patients with Multiple Myeloma (MM. A further step is to elucidate the mechanisms encoded by these genes yielding to drug resistance and/or patients' short survival. We focus here on the biological role of the DEP (for Disheveled, EGL-10, Pleckstrin domain contained protein 1A (DEPDC1A, a poorly known protein encoded by DEPDC1A gene, whose high expression in malignant plasma cells is associated with short survival of patients. Using conditional lentiviral vector delivery of DEPDC1A shRNA, we report that DEPDC1A knockdown delayed the growth of human myeloma cell lines (HMCLs, with a block in G2 phase of the cell cycle, p53 phosphorylation and stabilization, and p21(Cip1 accumulation. DEPDC1A knockdown also resulted in increased expression of mature plasma cell markers, including CXCR4, IL6-R and CD38. Thus DEPDC1A could contribute to the plasmablast features of MMCs found in some patients with adverse prognosis, blocking the differentiation of malignant plasma cells and promoting cell cycle.

The use of cell phones and radio communication systems to reduce delays in getting help for pregnant women in low- and middle-income countries: a scoping review.

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Oyeyemi, Sunday O; Wynn, Rolf

2015-01-01

Delays in getting medical help are important factors in the deaths of many pregnant women and unborn children in the low- and middle-income countries (LMIC). Studies have suggested that the use of cell phones and radio communication systems might reduce such delays. We review the literature regarding the impact of cell phones and radio communication systems on delays in getting medical help by pregnant women in the LMIC. Cochrane Library, PubMed, Maternity and Infant care (Ovid), Web of Science (ISI), and Google Scholar were searched for studies relating to the use of cell phones for maternal and child health services, supplemented with hand searches. We included studies in LMIC and in English involving the simple use of cell phones (or radio communication) to either make calls or send text messages. Fifteen studies met the inclusion criteria. All the studies, while of various designs, demonstrated positive contributory effects of cell phones or radio communication systems in reducing delays experienced by pregnant women in getting medical help. While the results suggested that cell phones could contribute in reducing delays, more studies of a longer duration are needed to strengthen the finding.

The use of cell phones and radio communication systems to reduce delays in getting help for pregnant women in low- and middle-income countries: a scoping review

Directory of Open Access Journals (Sweden)

Sunday O. Oyeyemi

2015-09-01

Full Text Available Background: Delays in getting medical help are important factors in the deaths of many pregnant women and unborn children in the low- and middle-income countries (LMIC. Studies have suggested that the use of cell phones and radio communication systems might reduce such delays. Objectives: We review the literature regarding the impact of cell phones and radio communication systems on delays in getting medical help by pregnant women in the LMIC. Design: Cochrane Library, PubMed, Maternity and Infant care (Ovid, Web of Science (ISI, and Google Scholar were searched for studies relating to the use of cell phones for maternal and child health services, supplemented with hand searches. We included studies in LMIC and in English involving the simple use of cell phones (or radio communication to either make calls or send text messages. Results: Fifteen studies met the inclusion criteria. All the studies, while of various designs, demonstrated positive contributory effects of cell phones or radio communication systems in reducing delays experienced by pregnant women in getting medical help. Conclusions: While the results suggested that cell phones could contribute in reducing delays, more studies of a longer duration are needed to strengthen the finding.

Influence of distributed delays on the dynamics of a generalized immune system cancerous cells interactions model

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Piotrowska, M. J.; Bodnar, M.

2018-01-01

We present a generalisation of the mathematical models describing the interactions between the immune system and tumour cells which takes into account distributed time delays. For the analytical study we do not assume any particular form of the stimulus function describing the immune system reaction to presence of tumour cells but we only postulate its general properties. We analyse basic mathematical properties of the considered model such as existence and uniqueness of the solutions. Next, we discuss the existence of the stationary solutions and analytically investigate their stability depending on the forms of considered probability densities that is: Erlang, triangular and uniform probability densities separated or not from zero. Particular instability results are obtained for a general type of probability densities. Our results are compared with those for the model with discrete delays know from the literature. In addition, for each considered type of probability density, the model is fitted to the experimental data for the mice B-cell lymphoma showing mean square errors at the same comparable level. For estimated sets of parameters we discuss possibility of stabilisation of the tumour dormant steady state. Instability of this steady state results in uncontrolled tumour growth. In order to perform numerical simulation, following the idea of linear chain trick, we derive numerical procedures that allow us to solve systems with considered probability densities using standard algorithm for ordinary differential equations or differential equations with discrete delays.

Delayed-rectifier K channels contribute to contrast adaptation in mammalian retinal ganglion cells.

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Weick, Michael; Demb, Jonathan B

2011-07-14

Retinal ganglion cells adapt by reducing their sensitivity during periods of high contrast. Contrast adaptation in the firing response depends on both presynaptic and intrinsic mechanisms. Here, we investigated intrinsic mechanisms for contrast adaptation in OFF Alpha ganglion cells in the in vitro guinea pig retina. Using either visual stimulation or current injection, we show that brief depolarization evoked spiking and suppressed firing during subsequent depolarization. The suppression could be explained by Na channel inactivation, as shown in salamander cells. However, brief hyperpolarization in the physiological range (5-10 mV) also suppressed firing during subsequent depolarization. This suppression was selectively sensitive to blockers of delayed-rectifier K channels (K(DR)). In somatic membrane patches, we observed tetraethylammonium-sensitive K(DR) currents that activated near -25 mV. Recovery from inactivation occurred at potentials hyperpolarized to V(rest). Brief periods of hyperpolarization apparently remove K(DR) inactivation and thereby increase the channel pool available to suppress excitability during subsequent depolarization. Copyright © 2011 Elsevier Inc. All rights reserved.

Dynamics of human T-cell lymphotropic virus I (HTLV-I) infection of CD4+ T-cells.

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Katri, Patricia; Ruan, Shigui

2004-11-01

Stilianakis and Seydel (Bull. Math. Biol., 1999) proposed an ODE model that describes the T-cell dynamics of human T-cell lymphotropic virus I (HTLV-I) infection and the development of adult T-cell leukemia (ATL). Their model consists of four components: uninfected healthy CD4+ T-cells, latently infected CD4+ T-cells, actively infected CD4+ T-cells, and ATL cells. Mathematical analysis that completely determines the global dynamics of this model has been done by Wang et al. (Math. Biosci., 2002). In this note, we first modify the parameters of the model to distinguish between contact and infectivity rates. Then we introduce a discrete time delay to the model to describe the time between emission of contagious particles by active CD4+ T-cells and infection of pure cells. Using the results in Culshaw and Ruan (Math. Biosci., 2000) in the analysis of time delay with respect to cell-free viral spread of HIV, we study the effect of time delay on the stability of the endemically infected equilibrium. Numerical simulations are presented to illustrate the results.

A study on stability and medical implications for a complex delay model for CML with cell competition and treatment.

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Rădulescu, I R; Cândea, D; Halanay, A

2014-12-21

We study a mathematical model describing the dynamics of leukemic and normal cell populations (stem-like and differentiated) in chronic myeloid leukemia (CML). This model is a system of four delay differential equations incorporating three types of cell division. The competition between normal and leukemic stem cell populations for the common microenvironment is taken into consideration. The stability of one steady state is investigated. The results are discussed via their medical interpretation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Complete horizontal skin cell resurfacing and delayed vertical cell infiltration into porcine reconstructive tissue matrix compared to bovine collagen matrix and human dermis.

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Mirastschijski, Ursula; Kerzel, Corinna; Schnabel, Reinhild; Strauss, Sarah; Breuing, Karl-Heinz

2013-10-01

Xenogenous dermal matrices are used for hernia repair and breast reconstruction. Full-thickness skin replacement is needed after burn or degloving injuries with exposure of tendons or bones. The authors used a human skin organ culture model to study whether porcine reconstructive tissue matrix (Strattice) is effective as a dermal tissue replacement. Skin cells or split-thickness skin grafts were seeded onto human deepidermized dermis, Strattice, and Matriderm. Cellular resurfacing and matrix infiltration were monitored by live fluorescence imaging, histology, and electron microscopy. Proliferation, apoptosis, cell differentiation, and adhesion were analyzed by immunohistochemistry. Epithelial resurfacing and vertical proliferation were reduced and delayed with both bioartificial matrices compared with deepidermized dermis; however, no differences in apoptosis, cell differentiation, or basement membrane formation were found. Vertical penetration was greatest on Matriderm, whereas no matrix infiltration was found on Strattice in the first 12 days. Uncompromised horizontal resurfacing was greatest with Strattice but was absent with Matriderm. Strattice showed no stimulatory effect on cellular inflammation. Matrix texture and surface properties governed cellular performance on tissues. Although dense dermal compaction delayed vertical cellular ingrowth for Strattice, it allowed uncompromised horizontal resurfacing. Dense dermal compaction may slow matrix decomposition and result in prolonged biomechanical stability of the graft. Reconstructive surgeons should choose the adequate matrix substitute depending on biomechanical requirements at the recipient site. Strattice may be suitable as a dermal replacement at recipient sites with high mechanical load requirements.

Simulation of E. coli gene regulation including overlapping cell cycles, growth, division, time delays and noise.

Directory of Open Access Journals (Sweden)

Ruoyu Luo

Full Text Available Due to the complexity of biological systems, simulation of biological networks is necessary but sometimes complicated. The classic stochastic simulation algorithm (SSA by Gillespie and its modified versions are widely used to simulate the stochastic dynamics of biochemical reaction systems. However, it has remained a challenge to implement accurate and efficient simulation algorithms for general reaction schemes in growing cells. Here, we present a modeling and simulation tool, called 'GeneCircuits', which is specifically developed to simulate gene-regulation in exponentially growing bacterial cells (such as E. coli with overlapping cell cycles. Our tool integrates three specific features of these cells that are not generally included in SSA tools: 1 the time delay between the regulation and synthesis of proteins that is due to transcription and translation processes; 2 cell cycle-dependent periodic changes of gene dosage; and 3 variations in the propensities of chemical reactions that have time-dependent reaction rates as a consequence of volume expansion and cell division. We give three biologically relevant examples to illustrate the use of our simulation tool in quantitative studies of systems biology and synthetic biology.

FACT prevents the accumulation of free histones evicted from transcribed chromatin and a subsequent cell cycle delay in G1.

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Macarena Morillo-Huesca

2010-05-01

Full Text Available The FACT complex participates in chromatin assembly and disassembly during transcription elongation. The yeast mutants affected in the SPT16 gene, which encodes one of the FACT subunits, alter the expression of G1 cyclins and exhibit defects in the G1/S transition. Here we show that the dysfunction of chromatin reassembly factors, like FACT or Spt6, down-regulates the expression of the gene encoding the cyclin that modulates the G1 length (CLN3 in START by specifically triggering the repression of its promoter. The G1 delay undergone by spt16 mutants is not mediated by the DNA-damage checkpoint, although the mutation of RAD53, which is otherwise involved in histone degradation, enhances the cell-cycle defects of spt16-197. We reveal how FACT dysfunction triggers an accumulation of free histones evicted from transcribed chromatin. This accumulation is enhanced in a rad53 background and leads to a delay in G1. Consistently, we show that the overexpression of histones in wild-type cells down-regulates CLN3 in START and causes a delay in G1. Our work shows that chromatin reassembly factors are essential players in controlling the free histones potentially released from transcribed chromatin and describes a new cell cycle phenomenon that allows cells to respond to excess histones before starting DNA replication.

A microtubule inhibitor, ABT-751, induces autophagy and delays apoptosis in Huh-7 cells

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Wei, Ren-Jie [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Department of Pathology, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan (China); Lin, Su-Shuan [Department of Pathology, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan (China); Wu, Wen-Ren [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Chen, Lih-Ren [Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan (China); Division of Physiology, Livestock Research Institute, Council of Agriculture, Taiwan (China); Li, Chien-Feng [Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan (China); Department of Pathology, Chi-Mei Medical Center, Tainan, Taiwan (China); National Institute of Cancer Research, National Health Research Institute, Tainan, Taiwan (China); Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Chen, Han-De; Chou, Chien-Ting; Chen, Ya-Chun [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Liang, Shih-Shin [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Chien, Shang-Tao [Department of Pathology, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan (China); Shiue, Yow-Ling, E-mail: ylshiue@mail.nsysu.edu.tw [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

2016-11-15

The objective was to investigate the upstream mechanisms of apoptosis which were triggered by a novel anti-microtubule drug, ABT-751, in hepatocellular carcinoma-derived Huh-7 cells. Effects of ABT-751 were evaluated by immunocytochemistry, flow cytometric, alkaline comet, soft agar, immunoblotting, CytoID, green fluorescent protein-microtubule associated protein 1 light chain 3 beta detection, plasmid transfection, nuclear/cytosol fractionation, coimmunoprecipitation, quantitative reverse transcription-polymerase chain reaction, small-hairpin RNA interference and mitochondria/cytosol fractionation assays. Results showed that ABT-751 caused dysregulation of microtubule, collapse of mitochondrial membrane potential, generation of reactive oxygen species (ROS), DNA damage, G{sub 2}/M cell cycle arrest, inhibition of anchorage-independent cell growth and apoptosis in Huh-7 cells. ABT-751 also induced early autophagy via upregulation of nuclear TP53 and downregulation of the AKT serine/threonine kinase (AKT)/mechanistic target of rapamycin (MTOR) pathway. Through modulation of the expression levels of DNA damage checkpoint proteins and G{sub 2}/M cell cycle regulators, ABT-751 induced G{sub 2}/M cell cycle arrest. Subsequently, ABT-751 triggered apoptosis with marked downregulation of B-cell CLL/lymphoma 2, upregulation of mitochondrial BCL2 antagonist/killer 1 and BCL2 like 11 protein levels, and cleavages of caspase 8 (CASP8), CASP9, CASP3 and DNA fragmentation factor subunit alpha proteins. Suppression of ROS significantly decreased ABT-751-induced autophagic and apoptotic cells. Pharmacological inhibition of autophagy significantly increased the percentages of ABT-751-induced apoptotic cells. The autophagy induced by ABT-751 plays a protective role to postpone apoptosis by exerting adaptive responses following microtubule damage, ROS and/or impaired mitochondria. - Highlights: • An anti-microtubule agent, ABT-751, induces autophagy and apoptosis in Huh-7 cells. �

Effect of lycium barbarum polysaccharides on high glucose-induced retinal ganglion cell apoptosis, gene expression and delayed rectifier potassium current

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Xiao-Fei Ma

2017-05-01

Full Text Available Objective: To study the effect of lycium barbarum polysaccharides (LBP on high glucoseinduced retinal ganglion cell apoptosis, gene expression and delayed rectifier potassium current. Methods: RGC-5 retinal ganglion cell lines were cultured and divided into control group, high glucose group and LBP group that were treated with normal DMEM, highglucose DMEM as well as high-glucose DMEM containing 500 ng/mL LBP respectively. After treatment, the Annexin V-FITC/PI kits were used to measure the number of apoptotic cells, fluorescence quantitative PCR kits were used to determine the expression of apoptosis genes and antioxidant genes, and patch clamp was used to test delayed rectifier potassium current. Results: 12, 24, 36 and 48 h after intervention, the number of apoptotic cells of high glucose group was significantly higher than that of control group, and the number of apoptotic cells of LBP group was significantly lower than that of high glucose group (P<0.05; 24 and 48 h after intervention, c-fos, c-jun, caspase-3, caspase-9, Nrf-2, NQO1 and HO-1 mRNA expression as well as potassium current amplitude (IK and maximum conductance (Gmax of high glucose group were significantly higher than those of control group while half maximum activation voltage (V1/2 was significantly lower than that of control group (P<0.05; c-fos, c-jun, caspase-3 and caspase-9 mRNA expression as well as IK and Gmax of LBP group were significantly lower than those of high glucose group, while Nrf-2, NQO1 and HO-1 mRNA expression as well as V1/2 of LBP group were significantly higher than those of high glucose group (P<0.05. Conclusions: LBP can reduce the high glucose-induced retinal ganglion cell apoptosis and inhibit the delayed rectifier potassium current amplitude.

miR-378 attenuates muscle regeneration by delaying satellite cell activation and differentiation in mice.

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Zeng, Ping; Han, Wanhong; Li, Changyin; Li, Hu; Zhu, Dahai; Zhang, Yong; Liu, Xiaohong

2016-09-01

Skeletal muscle mass and homeostasis during postnatal muscle development and regeneration largely depend on adult muscle stem cells (satellite cells). We recently showed that global overexpression of miR-378 significantly reduced skeletal muscle mass in mice. In the current study, we used miR-378 transgenic (Tg) mice to assess the in vivo functional effects of miR-378 on skeletal muscle growth and regeneration. Cross-sectional analysis of skeletal muscle tissues showed that the number and size of myofibers were significantly lower in miR-378 Tg mice than in wild-type mice. Attenuated cardiotoxin-induced muscle regeneration in miR-378 Tg mice was found to be associated with delayed satellite cell activation and differentiation. Mechanistically, miR-378 was found to directly target Igf1r in muscle cells both in vitro and in vivo These miR-378 Tg mice may provide a model for investigating the physiological and pathological roles of skeletal muscle in muscle-associated diseases in humans, particularly in sarcopenia. © The Author 2016. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Systemic treatment with CAR-engineered T cells against PSCA delays subcutaneous tumor growth and prolongs survival of mice

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Hillerdal, Victoria; Ramachandran, Mohanraj; Leja, Justyna; Essand, Magnus

2014-01-01

Adoptive transfer of T cells genetically engineered with a chimeric antigen receptor (CAR) has successfully been used to treat both chronic and acute lymphocytic leukemia as well as other hematological cancers. Experimental therapy with CAR-engineered T cells has also shown promising results on solid tumors. The prostate stem cell antigen (PSCA) is a protein expressed on the surface of prostate epithelial cells as well as in primary and metastatic prostate cancer cells and therefore a promising target for immunotherapy of prostate cancer. We developed a third-generation CAR against PSCA including the CD28, OX-40 and CD3 ζ signaling domains. T cells were transduced with a lentivirus encoding the PSCA-CAR and evaluated for cytokine production (paired Student’s t-test), proliferation (paired Student’s t-test), CD107a expression (paired Student’s t-test) and target cell killing in vitro and tumor growth and survival in vivo (Log-rank test comparing Kaplan-Meier survival curves). PSCA-CAR T cells exhibit specific interferon (IFN)-γ and interleukin (IL)-2 secretion and specific proliferation in response to PSCA-expressing target cells. Furthermore, the PSCA-CAR-engineered T cells efficiently kill PSCA-expressing tumor cells in vitro and systemic treatment with PSCA-CAR-engineered T cells significantly delays subcutaneous tumor growth and prolongs survival of mice. Our data confirms that PSCA-CAR T cells may be developed for treatment of prostate cancer

Delayed Activation Kinetics of Th2- and Th17 Cells Compared to Th1 Cells.

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Duechting, Andrea; Przybyla, Anna; Kuerten, Stefanie; Lehmann, Paul V

2017-09-12

During immune responses, different classes of T cells arise: Th1, Th2, and Th17. Mobilizing the right class plays a critical role in successful host defense and therefore defining the ratios of Th1/Th2/Th17 cells within the antigen-specific T cell repertoire is critical for immune monitoring purposes. Antigen-specific Th1, Th2, and Th17 cells can be detected by challenging peripheral blood mononuclear cells (PBMC) with antigen, and establishing the numbers of T cells producing the respective lead cytokine, IFN-γ and IL-2 for Th1 cells, IL-4 and IL-5 for Th2, and IL-17 for Th-17 cells, respectively. Traditionally, these cytokines are measured within 6 h in flow cytometry. We show here that 6 h of stimulation is sufficient to detect peptide-induced production of IFN-γ, but 24 h are required to reveal the full frequency of protein antigen-specific Th1 cells. Also the detection of IL-2 producing Th1 cells requires 24 h stimulation cultures. Measurements of IL-4 producing Th2 cells requires 48-h cultures and 96 h are required for frequency measurements of IL-5 and IL-17 secreting T cells. Therefore, accounting for the differential secretion kinetics of these cytokines is critical for the accurate determination of the frequencies and ratios of antigen-specific Th1, Th2, and Th17 cells.

12-Chloracetyl-PPD, a novel dammarane derivative, shows anti-cancer activity via delay the progression of cell cycle G2/M phase and reactive oxygen species-mediate cell apoptosis.

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Wang, Xu De; Sun, Yuan Yuan; Zhao, Chen; Qu, Fan Zhi; Zhao, Yu Qing

2017-03-05

(20R)-Dammarane-3β, 12β, 20, 25-tetrol (25-OH-PPD) is a ginsenoside isolated from Panax ginseng (C. A. Meyer). This compound exhibits anti-cancer activities on many human cancer cell lines. In this study, we investigated anti-cancer mechanisms of 12β-O-( L -Chloracetyl)-dammar-20(22)-ene-3β,25-diol(12-Chloracetyl-PPD), a modified 25-OH-PPD. We found that compound 12-Chloracetyl-PPD resulted in a concentration-dependent inhibition of viability in prostate, breast, and gastric cancer cells, without affecting the viability of normal cell (human gastric epithelial cell line-GES-1, hair follicle dermal papilla cell line-HHDPC and rat myocardial cell line-H9C2). In MDA-MB-435 and C4-2B cancer cells, 12-Chloracetyl-PPD induced G2/M cell cycle arrest, down-regulated mouse double minute 2 (MDM2) expression, up-regulated p53 expression, triggered apoptosis, and stimulated reactive oxygen species production. Apoptosis can be attenuated by the reactive oxygen species scavenger N-acetylcysteine. Our results suggested that compound 12-Chloracetyl-PPD showed obvious anti-cancer activity based on delaying cell cycle arrest and inducing cell apoptosis by reactive oxygen species production, which supported development of 12-Chloracetyl-PPD as a potential agent for cancer chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

[Effects of allitridum on rapidly delayed rectifier potassium current in HEK293 cell line].

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Zhang, Jiancheng; Lin, Kun; Wei, Zhixiong; Chen, Qian; Liu, Li; Zhao, Xiaojing; Zhao, Ying; Xu, Bin; Chen, Xi; Li, Yang

2015-08-01

To study the effect of allitridum on rapidly delayed rectifier potassium current (IKr) in HEK293 cell line. HEK293 cells were transiently transfected with HERG channel cDNA plasmid pcDNA3.1 via Lipofectamine. Allitridum was added to the extracellular solution by partial perfusion after giga seal at the final concentration of 30 µmol/L. Whole-cell patch clamp technique was used to record the HERG currents and gating kinetics before and after allitridum exposure at room temperature. The amplitude and density of IHERG were both suppressed by allitridum in a voltage-dependent manner. In the presence of allitridum, the peak current of IHERG was reduced from 73.5∓4.3 pA/pF to 42.1∓3.6 pA/pF at the test potential of +50 mV (P<0.01). Allitridum also concentration-dependently decreased the density of the IHERG. The IC50 of allitridum was 34.74 µmol/L with a Hill coefficient of 1.01. Allitridum at 30 µmol/L caused a significant positive shift of the steady-state activation curve of IHERG and a markedly negative shift of the steady-state inactivation of IHERG, and significantly shortened the slow time constants of IHERG deactivation. Allitridum can potently block IHERG in HEK293 cells, which might be the electrophysiological basis for its anti-arrhythmic action.

Chinese hamster ovary cell mitosis and its response to ionizing radiation: A morphological analysis of the living cell

International Nuclear Information System (INIS)

Carlson, J.G.

1989-01-01

Repeated microscopic observations of exponentially growing Chinese hamster ovary cells were made and the times and mitotic stages were recorded in control and irradiated cultures at 37 degree C. As determined by autoradiography, the time from the end of S phase to early prophase (the G2 phase) was 46 min, to breakdown of the nuclear envelope was 91 min, and to restoration of the nuclear envelope was 116 min. The time spent in morphologically distinguishable phases of mitosis and the effects of 0.5, 1.0, 1.5, 2.0, and 4.0 Gy of gamma or X radiation on cells at each phase were determined. Affected cells were found to be delayed without or with reversion to an earlier mitotic stage before recovering and advancing through mitosis. Cells were timed in the five steps comprising delay with reversion: inertia, cessation I, regression, cessation II, and reprogression. No cells treated in late prophase, i.e., within 8-10 min of nuclear envelope breakdown, were delayed by the doses used; therefore the critical or transition point must be situated in middle prophase. Cells irradiated in this stage were not delayed by 0.5 or 1.0 Gy, but suffered a dose-dependent delay with or without reversion after 1.5, 2.0, and 4.0 Gy. Cells irradiated in early prophase and very late interphase responded similarly, but a greater percentage of the latter reverted

Dose-rate effects on the cell cycle and survival of S3 HeLa and V79 cells

International Nuclear Information System (INIS)

Mitchell, J.B.; Bedford, J.S.; Bailey, S.M.

1979-01-01

The effects of continuous irradiation at different dose rates on the cell cycle and on cell survival were studied using synchronized S3 HeLa and V79 cells. The minimum dose rate necessary to stop cell division was found to be approximately 23 rad/hr for HeLa cells and 270 rad/hr for V79 cells. For dose rates that stop cell division, cells progress through G 1 and S, with a small delay in the S phase, and are blocked in G 2 . Appreciable mitotic accumulation was observed for HeLa cells at dose rates which stopped cell division. By comparison, much less mitotic accumulation was observed for V79 cells over a range of dose rates from 37 to 270 rad/hr. Minimum mitotic delays for a variety of dose rates were determined for both cell lines. S3 HeLa cells are much more sensitive in this respect than V79 cells; however, it appeared that for higher dose rates the minimum mitotic delay in HeLa cells asymptotically approached a value of about 35 hr. In addition to the qualitative differences observed for the two cell lines in regard to mitotic accumulation, HeLa cells accumulated for prolonged periods in the presence of colcemid while V79 cells were blocked for only a few hours, HeLa cells show a dramatic effect of redistribution of cells into sensitive phases of the cell cycle during exposure, which was reflected in the survival curves at low dose rate. More cell killing per unit dose was observed at 37 than at 74 rad/hr

Mitosis delay in cells of the root meristem of pea seedlings in S and G2-phases when irradiated with gamma-rays

International Nuclear Information System (INIS)

Gudkov, I.N.; Zezina, N.V.

1976-01-01

Irradiation (800 rads) of pea seedlings, synchronized by a 24-hr treatment with 0.03% hydroxyurea, at the stage of G 1 →S, induced a 12-hr delay of mitosis peak; an 8-hr delay, in the early S-phase; a 4-hr delay, in the middle of S-phase; a 10-hr delay in the late S- and a 14-16-hr delay, in G 2 -phase. The number of cells having chromosome aberrations at the mitosis peak was similar in all the phases under study

The comprehensive electrophysiological study of curcuminoids on delayed-rectifier K+ currents in insulin-secreting cells.

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Kuo, Ping-Chung; Yang, Chia-Jung; Lee, Yu-Chi; Chen, Pei-Chun; Liu, Yen-Chin; Wu, Sheng-Nan

2018-01-15

Curcumin (CUR) has been demonstrated to induce insulin release from pancreatic β-cells; however, how curcuminoids (including demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC)) exert any possible effects on membrane ion currents inherently in insulin-secreting cells remains largely unclear. The effects of CUR and other structurally similar curcuminoids on ion currents in rat insulin-secreting (INS-1) insulinoma cells were therefore investigated in this study. The effects of these compounds on ionic currents and membrane potential were studied by patch-clamp technique. CUR suppressed the amplitude of delayed-rectifier K + current (I K(DR) ) in a time-, state- and concentration-dependent manner in these cells and the inhibition was not reversed by diazoxide, nicorandil or chlorotoxin. The value of dissociation constant for CUR-induced suppression of I K(DR) in INS-1 cells was 1.26μM. Despite the inability of CUR to alter the activation rate of I K(DR) , it accelerated current inactivation elicited by membrane depolarization. Increasing CUR concentrations shifted the inactivation curve of I K(DR) to hyperpolarized potential and slowed the recovery of I K(DR) inactivation. CUR, DMC, and BDMC all exerted depressant actions on I K(DR) amplitude to a similar magnitude, although DMC and BDMC did not increase current inactivation clearly. CUR slightly suppressed the peak amplitude of voltage-gated Na + current. CUR, DMC and BDMC depolarized the resting potential and increased firing frequency of action potentials. The CUR-mediated decrease of I K(DR) and the increase of current inactivation also occurred in βTC-6 INS-1 cells. Taken these results together, these effects may be one of the possible mechanisms contributing their insulin-releasing effect. Copyright © 2017 Elsevier B.V. All rights reserved.

Improving Spiking Dynamical Networks: Accurate Delays, Higher-Order Synapses, and Time Cells.

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Voelker, Aaron R; Eliasmith, Chris

2018-03-01

Researchers building spiking neural networks face the challenge of improving the biological plausibility of their model networks while maintaining the ability to quantitatively characterize network behavior. In this work, we extend the theory behind the neural engineering framework (NEF), a method of building spiking dynamical networks, to permit the use of a broad class of synapse models while maintaining prescribed dynamics up to a given order. This theory improves our understanding of how low-level synaptic properties alter the accuracy of high-level computations in spiking dynamical networks. For completeness, we provide characterizations for both continuous-time (i.e., analog) and discrete-time (i.e., digital) simulations. We demonstrate the utility of these extensions by mapping an optimal delay line onto various spiking dynamical networks using higher-order models of the synapse. We show that these networks nonlinearly encode rolling windows of input history, using a scale invariant representation, with accuracy depending on the frequency content of the input signal. Finally, we reveal that these methods provide a novel explanation of time cell responses during a delay task, which have been observed throughout hippocampus, striatum, and cortex.

Cell-cycle distributions and radiation responses of Chinese hamster cells cultured continuously under hypoxic conditions

International Nuclear Information System (INIS)

Tokita, N.; Carpenter, S.G.; Raju, M.R.

1984-01-01

Cell-cycle distributions were measured by flow cytometry for Chinese hamster (CHO) cells cultured continuously under hypoxic conditions. DNA histograms showed an accumulation of cells in the early S phase followed by a traverse delay through the S phase, and a G 2 block. During hypoxic culturing, cell viability decreased rapidly to less than 0.1% at 120 h. Radiation responses for cells cultured under these conditions showed an extreme radioresistance at 72 h. Results suggest that hypoxia induces a condition similar to cell synchrony which itself changes the radioresistance of hypoxic cells. (author)

Attenuation of G2 cell cycle checkpoint control in human tumor cells is associated with increased frequencies of unrejoined chromosome breaks but not increased cytotoxicity following radiation exposure

International Nuclear Information System (INIS)

Schwartz, J.L.; Cowan, J.; Grdina, D.J.

1997-01-01

The contribution of G 2 cell cycle checkpoint control to ionizing radiation responses was examined in ten human tumor cell lines. Most of the delay in cell cycle progression seen in the first cell cycle following radiation exposure was due to blocks in G 2 and there were large cell line-to-cell line variations in the length of the G 2 block. Longer delays were seen in cell lines that had mutations in p53. There was a highly significant inverse correlation between the length of G 2 delay and the frequency of unrejoined chromosome breaks seen as chromosome terminal deletions in mitosis, and observation that supports the hypothesis that the signal for G 2 delay in mammalian cells is an unrejoined chromosome break. There were also an inverse correlation between the length of G 2 delay and the level of chromosome aneuploidy in each cell line, suggesting that the G 2 and mitotic spindel checkpoints may be linked to each other. Attenuation in G 2 checkpoint control was not associated with alterations in either the frequency of induced chromosome rearrangements or cell survival following radiation exposure suggesting that chromosome rearrangements, the major radiation-induced lethal lesion in tumor cells, form before cells enters G 2 . Thus, agents that act solely to override G 2 arrest should produce little radiosensitization in human tumor cells

Docetaxel modulates the delayed rectifier potassium current (IK) and ATP-sensitive potassium current (IKATP) in human breast cancer cells.

Science.gov (United States)

Sun, Tao; Song, Zhi-Guo; Jiang, Da-Qing; Nie, Hong-Guang; Han, Dong-Yun

2015-04-01

Ion channel expression and activity may be affected during tumor development and cancer growth. Activation of potassium (K(+)) channels in human breast cancer cells is reported to be involved in cell cycle progression. In this study, we investigated the effects of docetaxel on the delayed rectifier potassium current (I K) and the ATP-sensitive potassium current (I KATP) in two human breast cancer cell lines, MCF-7 and MDA-MB-435S, using the whole-cell patch-clamp technique. Our results show that docetaxel inhibited the I K and I KATP in both cell lines in a dose-dependent manner. Compared with the control at a potential of +60 mV, treatment with docetaxel at doses of 0.1, 1, 5, and 10 µM significantly decreased the I K in MCF-7 cells by 16.1 ± 3.5, 30.2 ± 5.2, 42.5 ± 4.3, and 46.4 ± 9% (n = 5, P < 0.05), respectively and also decreased the I KATP at +50 mV. Similar results were observed in MDA-MB-435S cells. The G-V curves showed no significant changes after treatment of either MCF-7 or MDA-MB-435S cells with 10 μM docetaxel. The datas indicate that the possible mechanisms of I K and I KATP inhibition by docetaxel may be responsible for its effect on the proliferation of human breast cancer cells.

Modeling PSA Problems - II: A Cell-to-Cell Transport Theory Approach

International Nuclear Information System (INIS)

Labeau, P.E.; Izquierdo, J.M.

2005-01-01

In the first paper of this series, we presented an extension of the classical theory of dynamic reliability in which the actual occurrence of an event causing a change in the system dynamics is possibly delayed. The concept of stimulus activation, which triggers the realization of an event after a distributed time delay, was introduced. This gives a new understanding of competing events in the sequence delineation process.In the context of the level-2 probabilistic safety analysis (PSA), the information on stimulus activation mainly consists of regions of the process variables space where the activation can occur with a given probability. The evolution equations of the extended theory of probabilistic dynamics are therefore particularized to a transport process between discrete cells defined in phase-space on this basis. Doing so, an integrated and coherent approach to level-2 PSA problems is propounded. This amounts to including the stimulus concept and the associated stochastic delays discussed in the first paper in the frame of a cell-to-cell transport process.In addition, this discrete model provides a theoretical basis for the definition of appropriate numerical schemes for integrated level-2 PSA applications

Analysis of cell-cycle regulation following exposure of lung-derived cells to γ-rays

Science.gov (United States)

Trani, D.; Lucchetti, C.; Cassone, M.; D'Agostino, L.; Caputi, M.; Giordano, A.

Acute exposure of mammalian cells to ionizing radiation results in a delay of cell-cycle progression and/or augmentation of apoptosis. Following ionizing radiation-induced DNA damage, cell-cycle arrest in the G1- or G2-phase of the cell-cycle prevents or delays DNA replication or mitosis, providing time for the DNA repair machinery to exert its function. Deregulation or failing of cell-cycle checkpoints and/or DNA repair mechanisms may lead normal cells bearing chromosome mutations to acquire neoplastic autonomy, which in turn can trigger the onset of cancer. Existing studies have focused on the impact of p53 status on the radiation response of lung cancer (LC) cell lines in terms of both cell-cycle regulation and apoptosis, while no comparative studies have been performed on the radiation response of lung derived normal and cancerous epithelial cells. To investigate the radiation response in normal and cancerous phenotypes, along with the role and impact of p53 status, and possible correlations with pRb/p105 or other proteins involved in carcinogenesis and cell-cycle regulation, we selected two lung-derived epithelial cell lines, one normal (NL20, p53 wild-type) and one non-small cell lung cancer (NSCLC), H358 (known to be p53-deficient). We compared the levels of γ-induced cell proliferation ability, cell-cycle arrest, apoptotic index, and expression levels of cell-cycle regulating and regulated proteins. The different cell sensitivity, apoptotic response and protein expression profiles resulting from our study for NL20 and H358 cells suggest that still unknown mechanisms involving p53, pRb/p105 and their target molecules might play a pivotal role in determining cell sensitivity and resistance upon exposure to ionizing radiation.

Luteal cell steroidogenesis in relation to delayed embryonic development in the Indian short-nosed fruit bat, Cynopterus sphinx.

Science.gov (United States)

Meenakumari, Karukayil J; Banerjee, Arnab; Krishna, Amitabh

2009-01-01

The primary aim of this study was to determine the possible cause of slow or delayed embryonic development in Cynopterus sphinx by investigating morphological and steroidogenic changes in the corpus luteum (CL) and circulating hormone concentrations during two pregnancies of a year. This species showed delayed post-implantational embryonic development during gastrulation of the first pregnancy. Morphological features of the CL showed normal luteinization during both pregnancies. The CL did not change significantly in luteal cell size during the delay period of the first pregnancy as compared with the second pregnancy. The circulating progesterone and 17beta-estradiol concentrations were significantly lower during the period of delayed embryonic development as compared with the same stage of embryonic development during the second pregnancy. We also showed a marked decline in the activity of 3beta-hydroxysteroid dehydrogenase, P450 side chain cleavage enzyme, and steroidogenic acute regulatory peptide in the CL during the delay period. This may cause low circulating progesterone and estradiol synthesis and consequently delay embryonic development. What causes the decrease in steroidogenic factors in the CL during the period of delayed development in C. sphinx is under investigation.

Induction of suppression of delayed type hypersensitivity to herpes simplex virus by epidermal cells exposed to UV-irradiated urocanic acid in vivo

International Nuclear Information System (INIS)

Ross, J.A.; Howie, S.E.; Norval, M.; Maingay, J.P.

1987-01-01

Urocanic acid (UCA), the putative photoreceptor for ultraviolet radiation (UV)-induced suppression, undergoes a UV-dependent trans to cis isomerisation. Epidermal cells from mice painted with UCA, containing a known proportion of the cis-isomer, generate suppression of the delayed type hypersensitivity response to herpes simplex virus type 1 (HSV-1) when transferred to naive syngeneic recipients at the same time and site as infection with HSV-1. One T suppressor cell subset, of phenotype (Thy1+, L3T4+, Ly2-), is induced by the cis-UCA modified epidermal cell transfer. Flow cytometric analysis of the epidermal cells from skin treated with UV or cis-UCA indicates an overall reduction from normal in the number of cells expressing MHC Class II antigens, but no alteration in the number expressing I-J antigens

Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells in irradiated bone marrow cell culture in vitro

International Nuclear Information System (INIS)

Fujitake, Hideki; Okamoto, Yuruko; Okubo, Hiroshi; Miyanomae, Takeshi; Kumagai, Keiko; Mori, K.J.

1981-01-01

Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells after irradiation were studied in the long-term culture of mouse bone marrow cells in vitro. No difference was observed in the survival of the stem cells among cultures in which 0 - 10 7 cells were re-inoculated on the adherent cell colonies in the culture flask. Stem cells showed a significant proliferation within 1 week and the number of the stem cells exceeded the control in 3 weeks after irradiation in the cultures with less than 10 6 re-inoculated cells per flask. In contrast, there was a considerable delay in the onset of stem cell proliferation after irradiation in the culture with 10 7 cells per flask. Based on these results, a possibility that a stimulator of stem cell proliferation, released from irradiated stromal cells, is cancelled by an inhibitory factor produced by irradiated or unirradiated haemopoietic cells is postulated. (author)

Delayed innocent bystander cell death following hypoxia in Caenorhabditis elegans.

Science.gov (United States)

Sun, C-L; Kim, E; Crowder, C M

2014-04-01

After hypoxia, cells may die immediately or have a protracted course, living or dying depending on an incompletely understood set of cell autonomous and nonautonomous factors. In stroke, for example, some neurons are thought to die from direct hypoxic injury by cell autonomous primary mechanisms, whereas other so called innocent bystander neurons die from factors released from the primarily injured cells. A major limitation in identifying these factors is the inability of current in vivo models to selectively target a set of cells for hypoxic injury so that the primarily injured cells and the innocent bystanders are clearly delineated. In order to develop such a model, we generated transgenic Caenorhabditis elegans strains where 2-3% of somatic cells were made selectively sensitive to hypoxia. This was accomplished by cell type-specific wild-type rescue in either pharyngeal myocytes or GABAergic neurons of a hypoxia resistance-producing translation factor mutation. Surprisingly, hypoxic targeting of these relatively small subsets of non-essential cells produced widespread innocent bystander cell injury, behavioral dysfunction and eventual organismal death. The hypoxic injury phenotypes of the myocyte or neuron sensitized strains were virtually identical. Using this model, we show that the C. elegans insulin receptor/FOXO transcription factor pathway improves survival when activated only after hypoxic injury and blocks innocent bystander death.

Combined application of neutrophin-3 gene and neural stem cells is ameliorative to delay of denervated skeletal muscular atrophy after tibial nerve transection in rats.

Science.gov (United States)

Lin, Sen; Xu, Jianguang; Hu, Shaonan; Xu, Lei; Zhang, Changqing; Wang, Yang; Gu, Yudong

2011-01-01

Examination of the therapeutic efficacy of neural stem cells (NSCs) has recently become the focus of much investigation. In this study we present an insight of the effects of combined application with neurotrophin-3 (NT-3) and NSCs that derived from rat embryo spinal cord on delaying denervated skeletal muscular atrophy after tibial nerve was severed. NT-3 gene was amplified by PCR and subcloned into lentiviral vector pWPXL-MOD to construct a lentiviral expression vector pWPXL-MOD-NT-3. A positive clone expressing NT-3 (named NSCs-NT-3) was obtained and used for differentiation in vitro and transplantation. Sixty adult rats, whose tibial nerves were sectioned, were divided into two groups: one grafted with NSCs-NT-3 (experimental group, n = 30) and the other with NSCs transfected by pWPXL-MOD (control group, n = 30). The cell survival and differentiation, NT-3 gene expression, and effect of delaying denervated skeletal muscular atrophy were examined through immunohistostaining, RT-PCR, Western blot, electrophysiological analysis, and mean cross-sectional area (CSA) of gastrocnemius, respectively. The results show that the NT-3 gene, which is comprised of 777 bp, was cloned and significantly different expression were detected between NSCs and NSCs-NT-3 in vitro. Quantitative analysis of the choline acetyltransferase (ChAT) immunopositive cells revealed a significant increase in experimental group compared to the control group 4 weeks after implantation (p ChAT immunopositive cells were detected near the engrafted region only in experimental group. Furthermore, the effect in delaying denervated skeletal muscular atrophy is indicated in the EMG examination and mean CSA of gastrocnemius. These findings suggest that the neural stem cells expressing NT-3 endogenously would be a better graft candidate for the delay of denervated skeletal muscular atrophy.

Microscopic time-resolved imaging of singlet oxygen by delayed fluorescence in living cells.

Science.gov (United States)

Scholz, Marek; Dědic, Roman; Hála, Jan

2017-11-08

Singlet oxygen is a highly reactive species which is involved in a number of processes, including photodynamic therapy of cancer. Its very weak near-infrared emission makes imaging of singlet oxygen in biological systems a long-term challenge. We address this challenge by introducing Singlet Oxygen Feedback Delayed Fluorescence (SOFDF) as a novel modality for semi-direct microscopic time-resolved wide-field imaging of singlet oxygen in biological systems. SOFDF has been investigated in individual fibroblast cells incubated with a well-known photosensitizer aluminium phthalocyanine tetrasulfonate. The SOFDF emission from the cells is several orders of magnitude stronger and much more readily detectable than the very weak near-infrared phosphorescence of singlet oxygen. Moreover, the analysis of SOFDF kinetics enables us to estimate the lifetimes of the involved excited states. Real-time SOFDF images with micrometer spatial resolution and submicrosecond temporal-resolution have been recorded. Interestingly, a steep decrease in the SOFDF intensity after the photodynamically induced release of a photosensitizer from lysosomes has been demonstrated. This effect could be potentially employed as a valuable diagnostic tool for monitoring and dosimetry in photodynamic therapy.

Delayed Accumulation of H3K27me3 on Nascent DNA Is Essential for Recruitment of Transcription Factors at Early Stages of Stem Cell Differentiation.

Science.gov (United States)

Petruk, Svetlana; Cai, Jingli; Sussman, Robyn; Sun, Guizhi; Kovermann, Sina K; Mariani, Samanta A; Calabretta, Bruno; McMahon, Steven B; Brock, Hugh W; Iacovitti, Lorraine; Mazo, Alexander

2017-04-20

Recruitment of transcription factors (TFs) to repressed genes in euchromatin is essential to activate new transcriptional programs during cell differentiation. However, recruitment of all TFs, including pioneer factors, is impeded by condensed H3K27me3-containing chromatin. Single-cell and gene-specific analyses revealed that, during the first hours of induction of differentiation of mammalian embryonic stem cells (ESCs), accumulation of the repressive histone mark H3K27me3 is delayed after DNA replication, indicative of a decondensed chromatin structure in all regions of the replicating genome. This delay provides a critical "window of opportunity" for recruitment of lineage-specific TFs to DNA. Increasing the levels of post-replicative H3K27me3 or preventing S phase entry inhibited recruitment of new TFs to DNA and significantly blocked cell differentiation. These findings suggest that recruitment of lineage-specifying TFs occurs soon after replication and is facilitated by a decondensed chromatin structure. This insight may explain the developmental plasticity of stem cells and facilitate their exploitation for therapeutic purposes. Copyright © 2017 Elsevier Inc. All rights reserved.

Delayed administration of neural stem cells after hypoxia-ischemia reduces sensorimotor deficits, cerebral lesion size, and neuroinflammation in neonatal mice

NARCIS (Netherlands)

Braccioli, Luca; Heijnen, Cobi J.; Coffer, Paul J.; Nijboer, Cora H.A.

2017-01-01

Background Hypoxic-ischemic (HI) encephalopathy causes mortality and severe morbidity in neonates. Treatments with a therapeutic window >6 hours are currently not available. Here we explored whether delayed transplantation of allogenic neural stem cells (NSCs) at 10 days after HI could be a tool to

[Effect of microRNA-34a/SIRT1/p53 signal pathway on notoginsenoside R₁ delaying vascular endothelial cell senescence].

Science.gov (United States)

Lai, Xiao-Hua; Lei, Yan; Yang, Jing; Xiu, Cheng-Kui

2018-02-01

This study aimed to investigate the effect of notoginsenoside R₁ in delaying H₂O₂-induced vascular endothelial cell senescence through microRNA-34a/SIRT1/p53 signal pathway. In this study， human umbilical vein endothelial cells(HUVECs) were selected as the study object; the aging model induced by hydrogen peroxide(H₂O₂) was established， with resveratrol as the positive drug. HUVECs were randomly divided into four groups， youth group， senescence model group， notoginsenoside R₁ group and resveratrol group. Notoginsenoside R₁ group and resveratrol group were modeled with 100 μmoL·L⁻¹ H₂O₂ for 4 h after 24 h treatment with notoginsenoside R₁(30 μmoL·L⁻¹) and resveratrol(10 μmoL·L⁻¹) respectively. At the end， each group was cultured with complete medium for 24 h. The degree of cellular senescence was detected by senescence-associated β-galactosidase(SA-β-Gal) staining kit， the cell viability was detected by cell counting kit-8， the cell cycle distribution was analyzed by flow cytometry， and the cellular SOD activity was detected by WST-1 method in each group. The expressions of SIRT1， p53， p21 and p16 proteins in HUVECs were detected by Western blot. In addition， the mRNA expressions of miRNA-34a， SIRT1 and p53 in HUVECs were assayed by Real-time PCR. These results indicated that notoginsenoside R₁ significantly reduced the positive staining rate of senescent cells， enhanced the cell proliferation capacity and intracellular SOD activity， decreased the proportion of cells in G₀/G₁ phase， and increased the percentage of cells in S phase simultaneously compared with the senescence model group. Moreover， notoginsenoside R₁ decreased the mRNA expressions of miRNA-34a and p53 and the protein expression of p53， p21 and p16.At the same time， notoginsenoside R₁ increased the protein and mRNA expressions of SIRT1. The differences in these results between the senescence model group and the

Stability and Hopf bifurcation on a model for HIV infection of CD4{sup +} T cells with delay

Energy Technology Data Exchange (ETDEWEB)

Wang Xia [College of Mathematics and Information Science, Xinyang Normal University, Xinyang, Henan 464000 (China)], E-mail: xywangxia@163.com; Tao Youde [College of Mathematics and Information Science, Xinyang Normal University, Xinyang, Henan 464000 (China); Beijing Institute of Information Control, Beijing 100037 (China); Song Xinyu [College of Mathematics and Information Science, Xinyang Normal University, Xinyang, Henan 464000 (China) and Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, Beijing 100091 (China)], E-mail: xysong88@163.com

2009-11-15

In this paper, a delayed differential equation model that describes HIV infection of CD4{sup +} T cells is considered. The stability of the positive equilibrium and the existence of Hopf bifurcation are investigated. In succession, using the normal form theory and center manifold argument, we derive the explicit formulas which determine the stability, direction and other properties of bifurcating periodic solutions.

Radiation-induced cell damage

International Nuclear Information System (INIS)

Felix, W.D.; Schneiderman, M.H.

1976-01-01

The addition of irradiated crystals of galactose to Chinese hamster ovary cells resulted in mitotic delay, whereas exposure to nonirradiated crystals resulted in no detectable delay. The inference from this preliminary data is that free radicals or other transient irradiation products have reacted with external cellular components

Attenuation of G{sub 2} cell cycle checkpoint control in human tumor cells is associated with increased frequencies of unrejoined chromosome breaks but not increased cytotoxicity following radiation exposure

Energy Technology Data Exchange (ETDEWEB)

Schwartz, J.L.; Cowan, J.; Grdina, D.J. [and others

1997-08-01

The contribution of G{sub 2} cell cycle checkpoint control to ionizing radiation responses was examined in ten human tumor cell lines. Most of the delay in cell cycle progression seen in the first cell cycle following radiation exposure was due to blocks in G{sub 2} and there were large cell line-to-cell line variations in the length of the G{sub 2} block. Longer delays were seen in cell lines that had mutations in p53. There was a highly significant inverse correlation between the length of G{sub 2} delay and the frequency of unrejoined chromosome breaks seen as chromosome terminal deletions in mitosis, and observation that supports the hypothesis that the signal for G{sub 2} delay in mammalian cells is an unrejoined chromosome break. There were also an inverse correlation between the length of G{sub 2} delay and the level of chromosome aneuploidy in each cell line, suggesting that the G{sub 2} and mitotic spindel checkpoints may be linked to each other. Attenuation in G{sub 2} checkpoint control was not associated with alterations in either the frequency of induced chromosome rearrangements or cell survival following radiation exposure suggesting that chromosome rearrangements, the major radiation-induced lethal lesion in tumor cells, form before cells enters G{sub 2}. Thus, agents that act solely to override G{sub 2} arrest should produce little radiosensitization in human tumor cells.

Pretransplantation recipient regulatory T cell suppressive function predicts delayed and slow graft function after kidney transplantation.

Science.gov (United States)

Nguyen, Minh-Tri J P; Fryml, Elise; Sahakian, Sossy K; Liu, Shuqing; Michel, Rene P; Lipman, Mark L; Mucsi, Istvan; Cantarovich, Marcelo; Tchervenkov, Jean I; Paraskevas, Steven

2014-10-15

Delayed graft function (DGF) and slow graft function (SGF) are a continuous spectrum of ischemia-reperfusion-related acute kidney injury (AKI) that increases the risk for acute rejection and graft loss after kidney transplantation. Regulatory T cells (Tregs) are critical in transplant tolerance and attenuate murine AKI. In this prospective observational cohort study, we evaluated whether pretransplantation peripheral blood recipient Treg frequency and suppressive function are predictors of DGF and SGF after kidney transplantation. Deceased donor kidney transplant recipients (n=53) were divided into AKI (n=37; DGF, n=10; SGF, n=27) and immediate graft function (n=16) groups. Pretransplantation peripheral blood CD4CD25FoxP3 Treg frequency was quantified by flow cytometry. Regulatory T-cell suppressive function was measured by suppression of autologous effector T-cell proliferation by Treg in co-culture. Pretransplantation Treg suppressive function, but not frequency, was decreased in AKI recipients (Paccounting for the effects of cold ischemic time and donor age, Treg suppressive function discriminated DGF from immediate graft function recipients in multinomial logistic regression (odds ratio, 0.77; Pfunction is a potential independent pretransplantation predictor of DGF and SGF.

B cell depletion reduces T cell activation in pancreatic islets in a murine autoimmune diabetes model.

Science.gov (United States)

Da Rosa, Larissa C; Boldison, Joanne; De Leenheer, Evy; Davies, Joanne; Wen, Li; Wong, F Susan

2018-06-01

Type 1 diabetes is a T cell-mediated autoimmune disease characterised by the destruction of beta cells in the islets of Langerhans, resulting in deficient insulin production. B cell depletion therapy has proved successful in preventing diabetes and restoring euglycaemia in animal models of diabetes, as well as in preserving beta cell function in clinical trials in the short term. We aimed to report a full characterisation of B cell kinetics post B cell depletion, with a focus on pancreatic islets. Transgenic NOD mice with a human CD20 transgene expressed on B cells were injected with an anti-CD20 depleting antibody. B cells were analysed using multivariable flow cytometry. There was a 10 week delay in the onset of diabetes when comparing control and experimental groups, although the final difference in the diabetes incidence, following prolonged observation, was not statistically significant (p = 0.07). The co-stimulatory molecules CD80 and CD86 were reduced on stimulation of B cells during B cell depletion and repopulation. IL-10-producing regulatory B cells were not induced in repopulated B cells in the periphery, post anti-CD20 depletion. However, the early depletion of B cells had a marked effect on T cells in the local islet infiltrate. We demonstrated a lack of T cell activation, specifically with reduced CD44 expression and effector function, including IFN-γ production from both CD4 + and CD8 + T cells. These CD8 + T cells remained altered in the pancreatic islets long after B cell depletion and repopulation. Our findings suggest that B cell depletion can have an impact on T cell regulation, inducing a durable effect that is present long after repopulation. We suggest that this local effect of reducing autoimmune T cell activity contributes to delay in the onset of autoimmune diabetes.

The epigenetic agents suberoylanilide hydroxamic acid and 5‑AZA‑2' deoxycytidine decrease cell proliferation, induce cell death and delay the growth of MiaPaCa2 pancreatic cancer cells in vivo.

Science.gov (United States)

Susanto, Johana M; Colvin, Emily K; Pinese, Mark; Chang, David K; Pajic, Marina; Mawson, Amanda; Caldon, C Elizabeth; Musgrove, Elizabeth A; Henshall, Susan M; Sutherland, Robert L; Biankin, Andrew V; Scarlett, Christopher J

2015-05-01

Despite incremental advances in the diagnosis and treatment for pancreatic cancer (PC), the 5‑year survival rate remains <5%. Novel therapies to increase survival and quality of life for PC patients are desperately needed. Epigenetic thera-peutic agents such as histone deacetylase inhibitors (HDACi) and DNA methyltransferase inhibitors (DNMTi) have demonstrated therapeutic benefits in human cancer. We assessed the efficacy of these epigenetic therapeutic agents as potential therapies for PC using in vitro and in vivo models. Treatment with HDACi [suberoylanilide hydroxamic acid (SAHA)] and DNMTi [5‑AZA‑2' deoxycytidine (5‑AZA‑dc)] decreased cell proliferation in MiaPaCa2 cells, and SAHA treatment, with or without 5‑AZA‑dc, resulted in higher cell death and lower DNA synthesis compared to 5‑AZA‑dc alone and controls (DMSO). Further, combination treatment with SAHA and 5‑AZA‑dc significantly increased expression of p21WAF1, leading to G1 arrest. Treatment with epigenetic agents delayed tumour growth in vivo, but did not decrease growth of established pancreatic tumours. In conclusion, these data demonstrate a potential role for epigenetic modifier drugs for the management of PC, specifically in the chemoprevention of PC, in combination with other chemotherapeutic agents.

Pan-Bcl-2 inhibitor obatoclax delays cell cycle progression and blocks migration of colorectal cancer cells.

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Bruno Christian Koehler

Full Text Available Despite the fact that new treatment regimes have improved overall survival of patients challenged by colorectal cancer (CRC, prognosis in the metastatic situation is still restricted. The Bcl-2 family of proteins has been identified as promising anti cancer drug target. Even though small molecules targeting Bcl-2 proteins are in clinical trials, little is known regarding their effects on CRC. The aim of this study was to preclinically investigate the value of ABT-737 and Obatoclax as anticancer drugs for CRC treatment. The effects of the BH3-mimetics ABT-737 and Obatoclax on CRC cells were assessed using viability and apoptosis assays. Wound healing migration and boyden chamber invasion assays were applied. 3-dimensional cell cultures were used for long term assessment of invasion and proliferation. Clinically relevant concentrations of pan-Bcl-2 inhibitor Obatoclax did not induce cell death. In contrast, the BH3-mimetic ABT-737 induced apoptosis in a dose dependent manner. Obatoclax caused a cell line specific slowdown of CRC cell growth. Furthermore, Obatoclax, but not ABT-737, recovered E-Cadherin expression and led to impaired migration and invasion of CRC cells. The proliferative capacity and invasiveness of CRC cells was strikingly inhibited by low dose Obatoclax in long term 3-dimensional cell cultures. Obatoclax, but not ABT-737, caused a G1-phase arrest accompanied by a downregulation of Cyclin D1 and upregulation of p27 and p21. Overexpression of Mcl-1, Bcl-xL or Bcl-2 reversed the inhibitory effect of Obatoclax on migration but failed to restore the proliferative capacity of Obatoclax-treated CRC cells. The data presented indicate broad and multifaceted antitumor effects of the pan-Bcl-2 inhibitor Obatoclax on CRC cells. In contrast to ABT-737, Obatoclax inhibited migration, invasion and proliferation in sublethal doses. In summary, this study recommends pan-Bcl-2 inhibition as a promising approach for clinical trials in CRC.

Metformin kills and radiosensitizes cancer cells and preferentially kills cancer stem cells

Science.gov (United States)

Song, Chang W.; Lee, Hyemi; Dings, Ruud P. M.; Williams, Brent; Powers, John; Santos, Troy Dos; Choi, Bo-Hwa; Park, Heon Joo

2012-01-01

The anti-cancer effects of metformin, the most widely used drug for type 2 diabetes, alone or in combination with ionizing radiation were studied with MCF-7 human breast cancer cells and FSaII mouse fibrosarcoma cells. Clinically achievable concentrations of metformin caused significant clonogenic death in cancer cells. Importantly, metformin was preferentially cytotoxic to cancer stem cells relative to non-cancer stem cells. Metformin increased the radiosensitivity of cancer cells in vitro, and significantly enhanced the radiation-induced growth delay of FSaII tumors (s.c.) in the legs of C3H mice. Both metformin and ionizing radiation activated AMPK leading to inactivation of mTOR and suppression of its downstream effectors such as S6K1 and 4EBP1, a crucial signaling pathway for proliferation and survival of cancer cells, in vitro as well as in the in vivo tumors. Conclusion: Metformin kills and radiosensitizes cancer cells and eradicates radioresistant cancer stem cells by activating AMPK and suppressing mTOR. PMID:22500211

Radiosensitivity of mesothelioma cell lines

International Nuclear Information System (INIS)

Haekkinen, A.M.; Laasonen, A.; Linnainmaa, K.; Mattson, K.; Pyrhoenen, S.

1996-01-01

The present study was carried out in order to examine the radiosensitivity of malignant pleural mesothelioma cell lines. Cell kinetics, radiation-induced delay of the cell cycle and DNA ploidy of the cell lines were also determined. For comparison an HeLa and a human foetal fibroblast cell line were simultaneously explored. Six previously cytogenetically and histologically characterized mesothelioma tumor cell lines were applied. A rapid tiazolyl blue microtiter (MTT) assay was used to analyze radiosensitivity and cell kinetics and DNA ploidy of the cultured cells were determined by flow cytometry. The survival fraction after a dose of 2 Gy (SF2), parameters α and β of the linear quadratic model (LQ-model) and mean inactivation dose (D MID ) were also estimated. The DNA index of four cell lines equaled 1.0 and two cell lines equaled 1.5 and 1.6. Different mesothelioma cell lines showed a great variation in radiosensitivity. Mean survival fraction after a radiation dose of 2 Gy (SF2) was 0.60 and ranged from 0.36 to 0.81 and mean α value was 0.26 (range 0.48-0.083). The SF2 of the most sensitive diploid mesothelioma cell line was 0.36: Less than that of the foetal fibroblast cell line (0.49). The survival fractions (0.81 and 0.74) of the two most resistant cell lines, which also were aneuploid, were equal to that of the HeLa cell line (0.78). The α/β ratios of the most sensitive cell lines were almost an order of magnitude greater than those of the two most resistant cell lines. Radiation-induced delay of the most resistant aneuploid cell line was similar to that of HeLa cells but in the most sensitive (diploid cells) there was practically no entry into the G1 phase following the 2 Gy radiation dose during 36 h. (orig.)

Radiosensitivity of mesothelioma cell lines

Energy Technology Data Exchange (ETDEWEB)

Haekkinen, A.M. [Dept. of Oncology, Univ. Central Hospital, Helsinki (Finland); Laasonen, A. [Dept. of Pathology, Central Hospital of Etelae-Pohjanmaa, Seinaejoki (Finland); Linnainmaa, K. [Dept. of Industrial Hygiene and Toxicology, Inst. of Occupational Health, Helsinki (Finland); Mattson, K. [Dept. Pulmonary Medicine, Univ. Central Hospital, Helsinki (Finland); Pyrhoenen, S. [Dept. of Oncology, Univ. Central Hospital, Helsinki (Finland)

1996-10-01

The present study was carried out in order to examine the radiosensitivity of malignant pleural mesothelioma cell lines. Cell kinetics, radiation-induced delay of the cell cycle and DNA ploidy of the cell lines were also determined. For comparison an HeLa and a human foetal fibroblast cell line were simultaneously explored. Six previously cytogenetically and histologically characterized mesothelioma tumor cell lines were applied. A rapid tiazolyl blue microtiter (MTT) assay was used to analyze radiosensitivity and cell kinetics and DNA ploidy of the cultured cells were determined by flow cytometry. The survival fraction after a dose of 2 Gy (SF2), parameters {alpha} and {beta} of the linear quadratic model (LQ-model) and mean inactivation dose (D{sub MID}) were also estimated. The DNA index of four cell lines equaled 1.0 and two cell lines equaled 1.5 and 1.6. Different mesothelioma cell lines showed a great variation in radiosensitivity. Mean survival fraction after a radiation dose of 2 Gy (SF2) was 0.60 and ranged from 0.36 to 0.81 and mean {alpha} value was 0.26 (range 0.48-0.083). The SF2 of the most sensitive diploid mesothelioma cell line was 0.36: Less than that of the foetal fibroblast cell line (0.49). The survival fractions (0.81 and 0.74) of the two most resistant cell lines, which also were aneuploid, were equal to that of the HeLa cell line (0.78). The {alpha}/{beta} ratios of the most sensitive cell lines were almost an order of magnitude greater than those of the two most resistant cell lines. Radiation-induced delay of the most resistant aneuploid cell line was similar to that of HeLa cells but in the most sensitive (diploid cells) there was practically no entry into the G1 phase following the 2 Gy radiation dose during 36 h. (orig.).

Plasma Rich in Growth Factors Induces Cell Proliferation, Migration, Differentiation, and Cell Survival of Adipose-Derived Stem Cells.

Science.gov (United States)

Mellado-López, Maravillas; Griffeth, Richard J; Meseguer-Ripolles, Jose; Cugat, Ramón; García, Montserrat; Moreno-Manzano, Victoria

2017-01-01

Adipose-derived stem cells (ASCs) are a promising therapeutic alternative for tissue repair in various clinical applications. However, restrictive cell survival, differential tissue integration, and undirected cell differentiation after transplantation in a hostile microenvironment are complications that require refinement. Plasma rich in growth factors (PRGF) from platelet-rich plasma favors human and canine ASC survival, proliferation, and delaying human ASC senescence and autophagocytosis in comparison with serum-containing cultures. In addition, canine and human-derived ASCs efficiently differentiate into osteocytes, adipocytes, or chondrocytes in the presence of PRGF. PRGF treatment induces phosphorylation of AKT preventing ASC death induced by lethal concentrations of hydrogen peroxide. Indeed, AKT inhibition abolished the PRGF apoptosis prevention in ASC exposed to 100  μ M of hydrogen peroxide. Here, we show that canine ASCs respond to PRGF stimulus similarly to the human cells regarding cell survival and differentiation postulating the use of dogs as a suitable translational model. Overall, PRGF would be employed as a serum substitute for mesenchymal stem cell amplification to improve cell differentiation and as a preconditioning agent to prevent oxidative cell death.

Cell Morphology Change by the Ultraviolet Ray Irradiation

International Nuclear Information System (INIS)

Park, Myung Joo; Matuo, Yoichirou; Akiyama, Yoko; Izumi, Yoshinobu; Nishijima, Shigehiro

2009-01-01

The effect of low doses of ultraviolet (UV) irradiation on morphology changes of cell has been studied based on the observation of the cell length. It was shown that UV-irradiated cell has different behavior in comparison with nonirradiated cell. From the histogram of cell-length distribution, it was confirmed that cell cycle of non irradiated cell was 28 hours, and that cell cycle of irradiated cell with dose of 20 Jm -2 was delayed (39 hours), while irradiated cell with 40 Jm -2 and 60 Jm -2 did not divide and kept growing continuously. It was supposed that in case of 20 Jm -2 of irradiation dose, the cell cycle was delayed because the checkpoint worked in order to repair DNA damage induced by generation of pyrimidine dimer, reactive oxygen species and so on. It was also supposed that in case of 40 Jm -2 and 60 Jm -2 of irradiation dose, overgrowth was induced because the checkpoint was not worked well. The morphology of overgrown cell was similar to that of normally senescent cell. Therefore, it was considered that cell senescence was accelerated by UV irradiation with irradiation doses of 40 Jm -2 and 60 Jm -2

Colony stimulating factor 1 receptor inhibition delays recurrence of glioblastoma after radiation by altering myeloid cell recruitment and polarization

Science.gov (United States)

Stafford, Jason H.; Hirai, Takahisa; Deng, Lei; Chernikova, Sophia B.; Urata, Kimiko; West, Brian L.; Brown, J. Martin

2016-01-01

Background Glioblastoma (GBM) may initially respond to treatment with ionizing radiation (IR), but the prognosis remains extremely poor because the tumors invariably recur. Using animal models, we previously showed that inhibiting stromal cell–derived factor 1 signaling can prevent or delay GBM recurrence by blocking IR-induced recruitment of myeloid cells, specifically monocytes that give rise to tumor-associated macrophages. The present study was aimed at determining if inhibiting colony stimulating factor 1 (CSF-1) signaling could be used as an alternative strategy to target pro-tumorigenic myeloid cells recruited to irradiated GBM. Methods To inhibit CSF-1 signaling in myeloid cells, we used PLX3397, a small molecule that potently inhibits the tyrosine kinase activity of the CSF-1 receptor (CSF-1R). Combined IR and PLX3397 therapy was compared with IR alone using 2 different human GBM intracranial xenograft models. Results GBM xenografts treated with IR upregulated CSF-1R ligand expression and increased the number of CD11b+ myeloid-derived cells in the tumors. Treatment with PLX3397 both depleted CD11b+ cells and potentiated the response of the intracranial tumors to IR. Median survival was significantly longer for mice receiving combined therapy versus IR alone. Analysis of myeloid cell differentiation markers indicated that CSF-1R inhibition prevented IR-recruited monocyte cells from differentiating into immunosuppressive, pro-angiogenic tumor-associated macrophages. Conclusion CSF-1R inhibition may be a promising strategy to improve GBM response to radiotherapy. PMID:26538619

Automatic analysis of dividing cells in live cell movies to detect mitotic delays and correlate phenotypes in time.

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Harder, Nathalie; Mora-Bermúdez, Felipe; Godinez, William J; Wünsche, Annelie; Eils, Roland; Ellenberg, Jan; Rohr, Karl

2009-11-01

Live-cell imaging allows detailed dynamic cellular phenotyping for cell biology and, in combination with small molecule or drug libraries, for high-content screening. Fully automated analysis of live cell movies has been hampered by the lack of computational approaches that allow tracking and recognition of individual cell fates over time in a precise manner. Here, we present a fully automated approach to analyze time-lapse movies of dividing cells. Our method dynamically categorizes cells into seven phases of the cell cycle and five aberrant morphological phenotypes over time. It reliably tracks cells and their progeny and can thus measure the length of mitotic phases and detect cause and effect if mitosis goes awry. We applied our computational scheme to annotate mitotic phenotypes induced by RNAi gene knockdown of CKAP5 (also known as ch-TOG) or by treatment with the drug nocodazole. Our approach can be readily applied to comparable assays aiming at uncovering the dynamic cause of cell division phenotypes.

Vertical propagation of waves in the solar atmosphere. II. Phase delays in the quiet chromosphere and cell-network distinctions

International Nuclear Information System (INIS)

Lites, B.W.; Chipman, E.G.; White, O.R.

1982-01-01

The differences in the phase of the velocity oscillations between a pair of chromospheric Ca II lines was measured using the Vacuum Tower Telescope at the Sacramento Peak Observatory. The observed phase differences indicate that the acoustic modes are trapped or envanescent, rather than propagating in the chromosphere. We find systematic distinctions in the phase delays between quiet network and cell interior regions for both intensity and velocity oscillations in photospheric and chromospheric lines. The theory of linear perturbations in a isothermal atmosphere is invoked to interpret these differences. From this analysis we find that one or more of the following explanations is possible. (1) the radiative damping is more effective in the network than in the cell interior; (2) the network features exclude oscillations of large horizontal wavenumber; or (3) the scale height of the chromosphere is larger in the network than in the cell interior

When stem cells grow old: phenotypes and mechanisms of stem cell aging

Science.gov (United States)

Schultz, Michael B.; Sinclair, David A.

2016-01-01

All multicellular organisms undergo a decline in tissue and organ function as they age. An attractive theory is that a loss in stem cell number and/or activity over time causes this decline. In accordance with this theory, aging phenotypes have been described for stem cells of multiple tissues, including those of the hematopoietic system, intestine, muscle, brain, skin and germline. Here, we discuss recent advances in our understanding of why adult stem cells age and how this aging impacts diseases and lifespan. With this increased understanding, it is feasible to design and test interventions that delay stem cell aging and improve both health and lifespan. PMID:26732838

Skin-resident stem cells and wound healing.

Science.gov (United States)

Iwata, Yohei; Akamatsu, Hirohiko; Hasebe, Yuichi; Hasegawa, Seiji; Sugiura, Kazumitsu

2017-01-01

CD271 is common stem cell marker for the epidermis and dermis. We assessed a kinetic movement of epidermal and dermal CD271 + cells in the wound healing process to elucidate the possible involvement with chronic skin ulcers. Epidermal CD271 + cells were proliferated and migrated from 3 days after wounding. Purified epidermal CD271 + cells expressed higher TGFβ2 and VEGFα transcripts than CD271 - cells. Delayed wound healing was observed in the aged mice compared with young mice. During the wound healing process, the peak of dermal CD271 + cell accumulation was delayed in aged mice compared with young mice. The expression levels of collagen-1, -3, -5, F4-80, EGF, FGF2, TGFβ1, and IL-1α were significantly increased in young mice compared with aged mice. Furthermore, purified dermal CD271 + cells expressed higher FGF2, EGF, PDGFB, and TGFβ1 gene transcripts than CD271 - cells. These results suggested that epidermal and dermal CD271 + cells were closely associated with wound healing process by producing various growth factors. Epidermal and dermal CD271 + cells in chronic skin ulcer patients were significantly reduced compared with healthy controls. Thus, both epidermal and dermal stem cells can play an important role in wound healing process.

Centering Single Cells in Microgels via Delayed Crosslinking Supports Long-Term 3D Culture by Preventing Cell Escape

NARCIS (Netherlands)

Kamperman, Tom; Henke, Sieger; Visser, Claas Willem; Karperien, Marcel; Leijten, Jeroen

2017-01-01

Single-cell-laden microgels support physiological 3D culture conditions while enabling straightforward handling and high-resolution readouts of individual cells. However, their widespread adoption for long-term cultures is limited by cell escape. In this work, it is demonstrated that cell escape is

Delayed effects of cold atmospheric plasma on vascular cells

NARCIS (Netherlands)

Stoffels, Eva; Roks, Anton J. M.; Deelmm, Leo E.

2008-01-01

We investigated the long-term behaviour of vascular cells (endothelial and smooth muscle) after exposure to a cold atmospheric plasma source. The cells were treated through a gas-permeable membrane, in order to simulate intravenous treatment with a gas plasma-filled catheter. Such indirect treatment

Delayed neuronal cell death in brainstem after transient brainstem ischemia in gerbils

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Hakuba Nobuhiro

2010-09-01

Full Text Available Abstract Background Because of the lack of reproducible brainstem ischemia models in rodents, the temporal profile of ischemic lesions in the brainstem after transient brainstem ischemia has not been evaluated intensively. Previously, we produced a reproducible brainstem ischemia model of Mongolian gerbils. Here, we showed the temporal profile of ischemic lesions after transient brainstem ischemia. Results Brainstem ischemia was produced by occlusion of the bilateral vertebral arteries just before their entry into the transverse foramina of the cervical vertebrae of Mongolian gerbils. Animals were subjected to brainstem ischemia for 15 min, and then reperfused for 0 d (just after ischemia, 1 d, 3 d and 7 d (n = 4 in each group. Sham-operated animals (n = 4 were used as control. After deep anesthesia, the gerbils were perfused with fixative for immunohistochemical investigation. Ischemic lesions were detected by immunostaining for microtubule-associated protein 2 (MAP2. Just after 15-min brainstem ischemia, ischemic lesions were detected in the lateral vestibular nucleus and the ventral part of the spinal trigeminal nucleus, and these ischemic lesions disappeared one day after reperfusion in all animals examined. However, 3 days and 7 days after reperfusion, ischemic lesions appeared again and clusters of ionized calcium-binding adapter molecule-1(IBA-1-positive cells were detected in the same areas in all animals. Conclusion These results suggest that delayed neuronal cell death took place in the brainstem after transient brainstem ischemia in gerbils.

Bone marrow stromal cells elicit tissue sparing after acute but not delayed transplantation into the contused adult rat thoracic spinal cord.

NARCIS (Netherlands)

Tewarie, R.D.; Hurtado, A.; Ritfeld, G.J.; Rahiem, S.T.; Wendell, D.F.; Barroso, M.M.; Grotenhuis, J.A.; Oudega, M.

2009-01-01

Bone marrow stromal cells (BMSC) transplanted into the contused spinal cord may support repair by improving tissue sparing. We injected allogeneic BMSC into the moderately contused adult rat thoracic spinal cord at 15 min (acute) and at 3, 7, and 21 days (delayed) post-injury and quantified tissue

Plasma Rich in Growth Factors Induces Cell Proliferation, Migration, Differentiation, and Cell Survival of Adipose-Derived Stem Cells

Directory of Open Access Journals (Sweden)

Maravillas Mellado-López

2017-01-01

Full Text Available Adipose-derived stem cells (ASCs are a promising therapeutic alternative for tissue repair in various clinical applications. However, restrictive cell survival, differential tissue integration, and undirected cell differentiation after transplantation in a hostile microenvironment are complications that require refinement. Plasma rich in growth factors (PRGF from platelet-rich plasma favors human and canine ASC survival, proliferation, and delaying human ASC senescence and autophagocytosis in comparison with serum-containing cultures. In addition, canine and human-derived ASCs efficiently differentiate into osteocytes, adipocytes, or chondrocytes in the presence of PRGF. PRGF treatment induces phosphorylation of AKT preventing ASC death induced by lethal concentrations of hydrogen peroxide. Indeed, AKT inhibition abolished the PRGF apoptosis prevention in ASC exposed to 100 μM of hydrogen peroxide. Here, we show that canine ASCs respond to PRGF stimulus similarly to the human cells regarding cell survival and differentiation postulating the use of dogs as a suitable translational model. Overall, PRGF would be employed as a serum substitute for mesenchymal stem cell amplification to improve cell differentiation and as a preconditioning agent to prevent oxidative cell death.

Adenosine A₂A receptors inhibit delayed rectifier potassium currents and cell differentiation in primary purified oligodendrocyte cultures.

Science.gov (United States)

Coppi, Elisabetta; Cellai, Lucrezia; Maraula, Giovanna; Pugliese, Anna Maria; Pedata, Felicita

2013-10-01

Oligodendrocyte progenitor cells (OPCs) are a population of cycling cells which persist in the adult central nervous system (CNS) where, under opportune stimuli, they differentiate into mature myelinating oligodendrocytes. Adenosine A(2A) receptors are Gs-coupled P1 purinergic receptors which are widely distributed throughout the CNS. It has been demonstrated that OPCs express A(2A) receptors, but their functional role in these cells remains elusive. Oligodendrocytes express distinct voltage-gated ion channels depending on their maturation. Here, by electrophysiological recordings coupled with immunocytochemical labeling, we studied the effects of adenosine A(2A) receptors on membrane currents and differentiation of purified primary OPCs isolated from the rat cortex. We found that the selective A(2A) agonist, CGS21680, inhibits sustained, delayed rectifier, K(+) currents (I(K)) without modifying transient (I(A)) conductances. The effect was observed in all cells tested, independently from time in culture. CGS21680 inhibition of I(K) current was concentration-dependent (10-200 nM) and blocked in the presence of the selective A(2A) antagonist SCH58261 (100 nM). It is known that I(K) currents play an important role during OPC development since their block decreases cell proliferation and differentiation. In light of these data, our further aim was to investigate whether A(2A) receptors modulate these processes. CGS21680, applied at 100 nM in the culture medium of oligodendrocyte cultures, inhibits OPC differentiation (an effect prevented by SCH58261) without affecting cell proliferation. Data demonstrate that cultured OPCs express functional A(2A) receptors whose activation negatively modulate I(K) currents. We propose that, by this mechanism, A(2A) adenosine receptors inhibit OPC differentiation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Antitumor Cell-Complex Vaccines Employing Genetically Modified Tumor Cells and Fibroblasts

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Antonio Miguel

2014-02-01

Full Text Available The present study evaluates the immune response mediated by vaccination with cell complexes composed of irradiated B16 tumor cells and mouse fibroblasts genetically modified to produce GM-CSF. The animals were vaccinated with free B16 cells or cell complexes. We employed two gene plasmid constructions: one high producer (pMok and a low producer (p2F. Tumor transplant was performed by injection of B16 tumor cells. Plasma levels of total IgG and its subtypes were measured by ELISA. Tumor volumes were measured and survival curves were obtained. The study resulted in a cell complex vaccine able to stimulate the immune system to produce specific anti-tumor membrane proteins (TMP IgG. In the groups vaccinated with cells transfected with the low producer plasmid, IgG production was higher when we used free B16 cell rather than cell complexes. Nonspecific autoimmune response caused by cell complex was not greater than that induced by the tumor cells alone. Groups vaccinated with B16 transfected with low producer plasmid reached a tumor growth delay of 92% (p ≤ 0.01. When vaccinated with cell complex, the best group was that transfected with high producer plasmid, reaching a tumor growth inhibition of 56% (p ≤ 0.05. Significant survival (40% was only observed in the groups vaccinated with free transfected B16 cells.

When stem cells grow old: phenotypes and mechanisms of stem cell aging.

Science.gov (United States)

Schultz, Michael B; Sinclair, David A

2016-01-01

All multicellular organisms undergo a decline in tissue and organ function as they age. An attractive theory is that a loss in stem cell number and/or activity over time causes this decline. In accordance with this theory, aging phenotypes have been described for stem cells of multiple tissues, including those of the hematopoietic system, intestine, muscle, brain, skin and germline. Here, we discuss recent advances in our understanding of why adult stem cells age and how this aging impacts diseases and lifespan. With this increased understanding, it is feasible to design and test interventions that delay stem cell aging and improve both health and lifespan. © 2016. Published by The Company of Biologists Ltd.

Herpes simplex virus produces larger plaques when assayed on ultraviolet irradiated CV1 cells

International Nuclear Information System (INIS)

Coohill, T.P.; Babich, M.A.; Taylor, W.D.; Snipes, W.

1980-01-01

Plaque development for either untreated or UV treated irradiated Herpes simplex virus Type 1 was faster when assayed on UV irradiated CV1 cells. This Large Plaque Effect only occurred if a minimum delay of 12h between cell irradiation and viral inoculation was allowed. Shorter delays gave plaques that were smaller than controls (unirradiated virus-unirradiated cells). The effect was maximal for a 48-h delay and remained unchanged for delays as long as 84h. The effect was greatest for cell exposures of 10Jm -2 . (author)

Breast cancer stem cell-like cells are more sensitive to ionizing radiation than non-stem cells: role of ATM.

Directory of Open Access Journals (Sweden)

Seog-Young Kim

Full Text Available There are contradictory observations about the different radiosensitivities of cancer stem cells and cancer non-stem cells. To resolve these contradictory observations, we studied radiosensitivities by employing breast cancer stem cell (CSC-like MDA-MB231 and MDA-MB453 cells as well as their corresponding non-stem cells. CSC-like cells proliferate without differentiating and have characteristics of tumor-initiating cells [1]. These cells were exposed to γ-rays (1.25-8.75 Gy and survival curves were determined by colony formation. A final slope, D(0, of the survival curve for each cell line was determined to measure radiosensitivity. The D(0 of CSC-like and non-stem MDA-MB-453 cells were 1.16 Gy and 1.55 Gy, respectively. Similar results were observed in MDA-MB-231 cells (0.94 Gy vs. 1.56 Gy. After determination of radiosensitivity, we investigated intrinsic cellular determinants which influence radiosensitivity including cell cycle distribution, free-radical scavengers and DNA repair. We observed that even though cell cycle status and antioxidant content may contribute to differential radiosensitivity, differential DNA repair capacity may be a greater determinant of radiosensitivity. Unlike non-stem cells, CSC-like cells have little/no sublethal damage repair, a low intracellular level of ataxia telangiectasia mutated (ATM and delay of γ-H2AX foci removal (DNA strand break repair. These results suggest that low DNA repair capacity is responsible for the high radiosensitivity of these CSC-like cells.

Defining Tumor Cell and Immune Cell Behavior in Vivo during Pulmonary Metastasis of Breast Cancer

Science.gov (United States)

2015-09-01

version of a manuscript detailing these findings in March of 2015. Following receipt of reviews our attention was placed on responding to reviewer...increased focus on this first manuscript our attention to the second major goal for this year was delayed. However, the key element of this goal...LIVM of CFP+ cell targeting cytoplast (see also Supplementary Video 8). Colours and tracking as in d. Tracked cells labelled as cell 1, 2 or 3 in

Dendritic cells: biology of the skin

NARCIS (Netherlands)

Toebak, M.J.; Gibbs, S.; Bruynzeel, D.P.; Scheper, R.J.; Rustemeyer, T.

2009-01-01

Allergic contact dermatitis results from a T-cell-mediated, delayed-type hypersensitivity immune response induced by allergens. Skin dendritic cells (DCs) play a central role in the initiation of allergic skin responses. Following encounter with an allergen, DCs become activated and undergo

Anandamide attenuates Th-17 cell-mediated delayed-type hypersensitivity response by triggering IL-10 production and consequent microRNA induction.

Directory of Open Access Journals (Sweden)

Austin R Jackson

Full Text Available Endogenous cannabinoids [endocannabinoids] are lipid signaling molecules that have been shown to modulate immune functions. However, their role in the regulation of Th17 cells has not been studied previously. In the current study, we used methylated Bovine Serum Albumin [mBSA]-induced delayed type hypersensitivity [DTH] response in C57BL/6 mice, mediated by Th17 cells, as a model to test the anti-inflammatory effects of endocannabinoids. Administration of anandamide [AEA], a member of the endocannabinoid family, into mice resulted in significant mitigation of mBSA-induced inflammation, including foot pad swelling, cell infiltration, and cell proliferation in the draining lymph nodes [LN]. AEA treatment significantly reduced IL-17 and IFN-γ production, as well as decreased RORγt expression while causing significant induction of IL-10 in the draining LNs. IL-10 was critical for the AEA-induced mitigation of DTH response inasmuch as neutralization of IL-10 reversed the effects of AEA. We next analyzed miRNA from the LN cells and found that 100 out of 609 miRNA species were differentially regulated in AEA-treated mice when compared to controls. Several of these miRNAs targeted proinflammatory mediators. Interestingly, many of these miRNA were also upregulated upon in vitro treatment of LN cells with IL-10. Together, the current study demonstrates that AEA may suppress Th-17 cell-mediated DTH response by inducing IL-10 which in turn triggers miRNA that target proinflammatory pathways.

Cell cycle regulation of human immunodeficiency virus type 1 integration in T cells: antagonistic effects of nuclear envelope breakdown and chromatin condensation

International Nuclear Information System (INIS)

Mannioui, Abdelkrim; Schiffer, Cecile; Felix, Nathalie

2004-01-01

We examined the influence of mitosis on the kinetics of human immunodeficiency virus type 1 integration in T cells. Single-round infection of cells arrested in G1b or allowed to synchronously proceed through division showed that mitosis delays virus integration until 18-24 h postinfection, whereas integration reaches maximum levels by 15 h in G1b-arrested cells. Subcellular fractionation of metaphase-arrested cells indicated that, while nuclear envelope disassembly facilitates docking of viral DNA to chromatin, chromosome condensation directly antagonizes and therefore delays integration. As a result of the balance between the two effects, virus integration efficiency is eventually up to threefold greater in dividing cells. At the single-cell level, using a green fluorescent protein-expressing reporter virus, we found that passage through mitosis leads to prominent asymmetric segregation of the viral genome in daughter cells without interfering with provirus expression

Host cell reactivation and UV-enhanced reactivation in synchronized mammalian cells

International Nuclear Information System (INIS)

Lytle, C.D.; Schmidt, B.J.

1981-01-01

Does host cell reactivation (HCR) or UV-enhanced reactivation (UVER) of UV-irradiated Herpes simplex virus (UV-HSV) vary during the host mammalian cell cycle. The answer could be useful for interpreting UVER and or the two-component nature of the UV-HSV survival curve. Procedures were developed for infection of mitotically-synchronized CV-l monkey kidney cells. All virus survival curves determined at different cell cycle stages had two components with similar D 0 's and intercepts of the second components. Thus, no single stage of the host cell cycle was responsible for the second component of the virus survival curve. When the cells were UV-irradiated immediately prior to infection, enhanced survival of UV-HSV occurred for cell irradiation and virus infection initiated during late G 1 early S phase or late S early G 2 phase but not during early G 1 phase. For infection delayed by 24 h after cell irradiation, UVER was found at all investigated times. These results indicate that: (1) HCR is similar at all stages of the host cell cycle: and (2) the ''induction'' of UVER is not as rapid for cell-irradiation in early G 1 phase. This latter observation may be one reason why normal, contact-inhibited cells do not express UVER as rapidly as faster growing, less contact-inhibited cells. (author)

The effects of energy beverages on cultured cells.

Science.gov (United States)

Doyle, Wayne; Shide, Eric; Thapa, Slesha; Chandrasekaran, Vidya

2012-10-01

The popularity and prevalence of energy beverages makes it essential to examine the interactions between the ingredients and their effects on the safety of these beverages. In this study, we used in vitro assays to examine the effects of two energy beverages on mesenchymal, epithelial and neuronal cells. Our results showed that treatment of epithelial and mesenchymal cells with either energy beverage resulted in a dose dependent delay in wound closure, in a scratch wound healing assay. In rat embryonic fibroblasts, treatment with the energy beverages led to decreased lamellipodia formation and decreased proliferation/viability; whereas in MDCK cells, energy beverage treatment resulted in actin disorganization without any effects on cell proliferation. This suggests that the mechanisms underlying delayed wound healing might be different in the two cell types. Interestingly, the delays in both cell types could not be mimicked by treatment of caffeine, taurine and glucose alone or in combinations. Furthermore, treatment of chick forebrain neuronal cultures with energy beverages resulted in a dose dependent inhibition of neurite outgrowth. The cellular assays used in this study provide a consistent, qualitative and quantitative system for examining the combinatorial effects of the various ingredients used in energy beverages. Copyright © 2012 Elsevier Ltd. All rights reserved.

Does defibrotide induce a delay to polymorphonuclear neutrophil engraftment after hematopoietic stem cell transplantation? Observation in a pediatric population.

Science.gov (United States)

Maximova, Natalia; Pizzol, Antonio; Giurici, Nagua; Granzotto, Marilena

2015-04-01

In recent years, defibrotide (DFT) has emerged as a promising therapy for veno-occlusive disease (VOD). The aim of this study was to investigate whether DFT prophylaxis affects neutrophil engraftment in patients undergoing hematopoietic stem cell transplantation (HSCT). A cohort of 44 consecutive pediatric patients who underwent HSCT was retrospectively analyzed to see the role of DFT on engraftment. Patients were assigned into two groups based on the use or non-use of prophylaxis with DFT. The mean time to engraftment was statistically different between the two groups for both polymorphonuclear neutrophils (PMN) and white blood cells. Our study supports the hypothesis that prophylaxis with DFT for VOD leads to a delay to the engraftment of PMN in pediatric patients that underwent HSCT.

Attenuation of p38α MAPK stress response signaling delays the in vivo aging of skeletal muscle myofibers and progenitor cells.

Science.gov (United States)

Papaconstantinou, John; Wang, Chen Z; Zhang, Min; Yang, San; Deford, James; Bulavin, Dmitry V; Ansari, Naseem H

2015-09-01

Functional competence and self-renewal of mammalian skeletal muscle myofibers and progenitor cells declines with age. Progression of the muscle aging phenotype involves the decline of juvenile protective factorsi.e., proteins whose beneficial functions translate directly to the quality of life, and self-renewal of progenitor cells. These characteristics occur simultaneously with the age-associated increase of p38α stress response signaling. This suggests that the maintenance of low levels of p38α activity of juvenile tissues may delay or attenuate aging. We used the dominant negative haploinsufficient p38α mouse (DN-p38α(AF/+)) to demonstrate that in vivo attenuation of p38α activity in the gastrocnemius of the aged mutant delays age-associated processes that include: a) the decline of the juvenile protective factors, BubR1, aldehyde dehydrogenase 1A (ALDH1A1), and aldehyde dehydrogenase 2 (ALDH2); b) attenuated expression of p16(Ink4a) and p19(Arf) tumor suppressor genes of the Cdkn2a locus; c) decreased levels of hydroxynonenal protein adducts, expression of COX2 and iNOS; d) decline of the senescent progenitor cell pool level and d) the loss of gastrocnemius muscle mass. We propose that elevated P-p38α activity promotes skeletal muscle aging and that the homeostasis of p38α impacts the maintenance of a beneficial healthspan.

Increasing Stem Cell Dose Promotes Posttransplant Immune Reconstitution.

Science.gov (United States)

Xu, Ning; Shen, Sylvie; Dolnikov, Alla

2017-04-01

Umbilical cord blood (UCB) transplantation can provide a successful therapeutic option for patients that have no suitable related donor. UCB transplantation is often limited by the relatively small hematopoietic stem cell (HSC) numbers in UCB especially for adult recipients. Early neutrophil and platelet engraftment correlates with the stem cell numbers in UCB transplant. Compared to other HSC sources, immune reconstitution following UCB transplant is slower and complicated by increased frequency of opportunistic infections. The effect of HSC numbers in UCB transplant on immune reconstitution was not thoroughly examined. Using immunocompromised mice transplanted with purified UCB CD34+ stem cells, we have demonstrated that increasing the numbers of CD34+ cells in the transplant promotes hematopoietic and immune reconstitution. At early stages posttransplant, high stem cell dose generated relatively more B cells, while lower dose generated more myeloid and T cells. Thus, the size of the stem cell graft appears to modulate the differentiation potential of infused stem cells. In addition, increasing stem cell dose in the transplant improved CD8+ T cell development and delayed late memory T cell skewing in expense of naive T cells highlighting the importance of HSC dose to maintain the pool of naive T cells able to develop strong immune responses. Transplantation of ex vivo expanded CD34+ cells did not promote, but rather delayed immune reconstitution suggesting the loss of primitive lymphoid precursor cells during ex vivo expansion.

Mechanosensation Dynamically Coordinates Polar Growth and Cell Wall Assembly to Promote Cell Survival.

Science.gov (United States)

Davì, Valeria; Tanimoto, Hirokazu; Ershov, Dmitry; Haupt, Armin; De Belly, Henry; Le Borgne, Rémi; Couturier, Etienne; Boudaoud, Arezki; Minc, Nicolas

2018-04-23

How growing cells cope with size expansion while ensuring mechanical integrity is not known. In walled cells, such as those of microbes and plants, growth and viability are both supported by a thin and rigid encasing cell wall (CW). We deciphered the dynamic mechanisms controlling wall surface assembly during cell growth, using a sub-resolution microscopy approach to monitor CW thickness in live rod-shaped fission yeast cells. We found that polar cell growth yielded wall thinning and that thickness negatively influenced growth. Thickness at growing tips exhibited a fluctuating behavior with thickening phases followed by thinning phases, indicative of a delayed feedback promoting thickness homeostasis. This feedback was mediated by mechanosensing through the CW integrity pathway, which probes strain in the wall to adjust synthase localization and activity to surface growth. Mutants defective in thickness homeostasis lysed by rupturing the wall, demonstrating its pivotal role for walled cell survival. Copyright © 2018 Elsevier Inc. All rights reserved.

Red blood cell alloimmunization in sickle cell disease patients in ...

African Journals Online (AJOL)

Objective: Alloimmunization is a recognized complication of red blood cell (RBC) transfusion and causes delayed hemolytic transfusion reactions and provides problems sourcing compatible blood for future transfusions. The objective of this study was to determine the frequency of RBC alloimmunization in SCD patients in ...

Cell cycle disturbances in slowly growing sublines isolated from X-irradiated L5178Y-S cell populations

International Nuclear Information System (INIS)

Beer, J.Z.; Bocian, E.; Budzicka, E.; Szumiel, I.; Ziemba-Zak, B.; Kopec, M.

1974-01-01

Cell cycle was analyzed autoradiographically in a test line of murine leukaemic lymphoblasts L5178Y-S and in two slowly growing sublines isolated from cell cultures irradiated with 300 rad of X-rays. It was found that prolongation of the cell cycle in the slowly growing sublines is connected primarily with delayed progression through G2 phase. This conclusion was further supported by results of determination of DNA content per cell in 13 slowly growing cell sublines and karyotype analysis of 18 sublines. No correlation was found between a sublines' mean doubling time and its chromosome number whereas DNA content per cell was clearly dependent on the growth rate. (author)

Effects of drugs, x-rays, and heat on Chinese hamster ovary cells

International Nuclear Information System (INIS)

Tomasovic, S.P.

1977-01-01

The mitotic cell selection technique was used to monitor the effects of various drugs, primarily inhibitors of RNA synthesis, on x-ray-induced G2 delay. Addition of actinomycin D (2 μg/ml), caffeine (19--194 μg/ml), theophylline (18--180 μg/ml), or cordycepin (5--30 μg/ml) immediately before or after irradiation greatly reduced G2 delay and shifted the x-ray transition point (X-TP, the point in G2 beyond which cells are unaffected in their progression by x-rays) away from division. The magnitude of this protective effect increased with concentration. Addition of dimethylsulfoxide (10 6 μg/ml) immediately after irradiation reduced G2 delay but had no effect on the X-TP. The addition of 2-mercapto-1(β-4-pyridethyl) benzimidazole (25--75 μg/ml) or lucanthone (5--20 μg/ml) immediately before irradiation resulted in increased G2 delay, and shifted the X-TP closer to division. Studies of the effects of these drugs on incorporation of tritiated uridine or tritiated leucine into acid insoluble material indicated no correlation between reduction of G2 delay and rates of overall RNA or protein synthesis. Synchronous cells, treated continuously with 15 μg/ml of cordycepin starting in the latter part of S phase, proceeded into mitosis about 30 minutes ahead of controls. Howevr, cordycepin did not reduce mitotic delay observed for cells irradiated in S phase. Continuous treatment during G2 of unirradiated synchronous cells with 15 μg/ml of cordycepin had little effect on accelerating cells into mitosis, yet did reduce delay observed for cells irradiated in G2. These results are consistent with hypotheses requiring synthesis during G2 of critical protein molecules essential for mitosis. Heating mammalian cells induces lethality by an undetermined mechanism. Heat treatment of Chinese hamster ovary cells at 45.5 0 C resulted in an increase in nonhistone protein isolated with DNA

Effect of gamma irradiation on proliferation and survival of Sf9 cells: radioresistance in a Lepidopteran insect cell line

International Nuclear Information System (INIS)

Seth, R.K.; Lovell, K.V.; Reynolds, S.E.

2003-01-01

Sf9 cells of Spodoptera frugiperda, when exposed to gamma-irradiation from a 60 Co source, were found markedly less sensitive to ionising radiation than mammalian cells in terms of both growth kinetics and survival. Following irradiation at 1.2 Gy S -1 there was a dose-dependent delay in Sf9 cell proliferation and plateau cell density was reduced. These effects were dependent on dose rate too. In the range 0.3 - 1.2 Gy s -1 , growth was delayed longer and reached a lower plateau with increasing dose rate. Exposure to radiation caused a decrease in adherence of cells to the substrate, and an increase in number of enlarged ('giant') cells. Analysis of colony formation after irradiation at 1.2 Gy s -1 gave a survival curve of conventional shape but with a very large D o value of 24 Gy. Extrapolation number (N) was 2.9, a value within the normal range for mammalian cells. At 0.12 Gy s -1 N had a similar value of 3.2, but D o was higher (30 Gy) than at the higher dose rate. This study indicates that the relative insensitivity of lepidoptera insects may be attributed to some extent to the intrinsic properties of their constituent cells. (author)

Sucralfate prevents the delay of wound repair in intestinal epithelial cells by hydrogen peroxide through NF-kappaB pathway.

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Shindo, Kenichi; Iizuka, Masahiro; Sasaki, Kenji; Konno, Shiho; Itou, Hiroaki; Horie, Yasuo; Watanabe, Sumio

2006-05-01

Recent studies have shown that sucralfate (SF) has therapeutic effects on colonic inflammation in ulcerative colitis. The aim of this study was to clarify the function of SF for wound repair in intestinal epithelial cells (IEC). (1) Activation of signal proteins [ERK1/2 mitogen-activated protein kinase (MAPK), IkappaB-alpha] in IEC-6 cells after stimulation with 10(-4) M potassium sucrose octasulfate (SOS), which is the functional element of SF, was assessed by Western blot. (2) Induction of transforming growth factor (TGF)-beta1, TGF-alpha, EGF, and cyclooxygenase-2 (COX-2) mRNA after stimulation of IEC-6 cells with SOS was assessed by reverse transcriptase-polymerase chain reaction. (3) IEC-6 cells were wounded and cultured for 24 h with various concentrations of SOS in the absence or presence of 20 microM H(2)O(2). Epithelial migration or proliferation was assessed by counting migrating cells or bromodeoxyuridine (BrdU)-positive cells across the wound border. (1) SOS activated IkappaB-alpha, but it did not activate ERK1/2 MAPK. (2) SOS enhanced the expression of COX-2 mRNA, but it did not change the mRNA expression of other growth factors. (3) SOS did not enhance wound repair in IEC-6 cells, but it decreased the number of dead cells (maximum, 74%) (P < 0.01) in a dose-dependent manner and prevented the diminishment of epithelial migration (maximum, 61%) (P < 0.01) and proliferation (maximum, 37%) (P < 0.05) induced by H(2)O(2). These functions of SOS were suppressed by the NF-kappaB and COX-2 inhibitors. SOS prevented the delay of wound repair in IEC-6 cells induced by H(2)O(2), probably through induction of COX-2 and an anti-apoptotic mechanism. These effects of SOS might be given through the activation of the NF-kappaB pathway.

Division delay after low x-ray doses and treatment with cyclohexionide

International Nuclear Information System (INIS)

Schneiderman, M.H.; Braby, L.A.; Roesch, W.C.

1977-01-01

Radiation-induced division delay of Chinese hamster ovary cells located in G 2 , and in G 2 between the cycloheximide and x-ray transition points, was measured by the mitotic cell selection technique. The mitotic yield (number of mitotic cells after treatment expressed as a fraction of the control) decreased with increasing radiation dose (4.5 to 34 rad). However, either because some cells were not delayed or because delayed cells recovered rapidly, the mitotic yield did not fall to zero. When cycloheximide was combined with radiation to prevent repair of the radiation damage, only cells which were past the cycloheximide transition point and not delayed by the radiation were selected. The location of the transition points determined from the combined drug plus low-dose radiation (4.5 to 34 rad) experiments indicate a dose-dependent relationship, with more cells delayed as the dose was increased. In addition, the transition point for cells treated with cycloheximide plus 150 rad of x rays was closer to division than the 150 rad of x rays alone. These results are discussed in light of a recent model for radiation-induced division delay proposed by Dewey and Highfield

Bifurcation analysis of a delayed mathematical model for tumor growth

International Nuclear Information System (INIS)

Khajanchi, Subhas

2015-01-01

In this study, we present a modified mathematical model of tumor growth by introducing discrete time delay in interaction terms. The model describes the interaction between tumor cells, healthy tissue cells (host cells) and immune effector cells. The goal of this study is to obtain a better compatibility with reality for which we introduced the discrete time delay in the interaction between tumor cells and host cells. We investigate the local stability of the non-negative equilibria and the existence of Hopf-bifurcation by considering the discrete time delay as a bifurcation parameter. We estimate the length of delay to preserve the stability of bifurcating periodic solutions, which gives an idea about the mode of action for controlling oscillations in the tumor growth. Numerical simulations of the model confirm the analytical findings

Delayed Mesoderm and Erythroid Differentiation of Murine Embryonic Stem Cells in the Absence of the Transcriptional Regulator FUBP1

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Josephine Wesely

2017-01-01

Full Text Available The transcriptional regulator far upstream binding protein 1 (FUBP1 is essential for fetal and adult hematopoietic stem cell (HSC self-renewal, and the constitutive absence of FUBP1 activity during early development leads to embryonic lethality in homozygous mutant mice. To investigate the role of FUBP1 in murine embryonic stem cells (ESCs and in particular during differentiation into hematopoietic lineages, we generated Fubp1 knockout (KO ESC clones using CRISPR/Cas9 technology. Although FUBP1 is expressed in undifferentiated ESCs and during spontaneous differentiation following aggregation into embryoid bodies (EBs, absence of FUBP1 did not affect ESC maintenance. Interestingly, we observed a delayed differentiation of FUBP1-deficient ESCs into the mesoderm germ layer, as indicated by impaired expression of several mesoderm markers including Brachyury at an early time point of ESC differentiation upon aggregation to EBs. Coculture experiments with OP9 cells in the presence of erythropoietin revealed a diminished differentiation capacity of Fubp1 KO ESCs into the erythroid lineage. Our data showed that FUBP1 is important for the onset of mesoderm differentiation and maturation of hematopoietic progenitor cells into the erythroid lineage, a finding that is supported by the phenotype of FUBP1-deficient mice.

Granulocyte-colony stimulating factor (G-CSF)-primed, delayed marrow harvests as a source of hematopoietic stem and progenitor cells for allogeneic transplantation.

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Phillips, G L; Davey, D D; Hale, G A; Marshall, K W; Munn, R K; Nath, R; Reece, D E; Van Zant, G

1999-10-01

We evaluated the ability of G-CSF to increase the number of hematopoietic stem cells obtained by "delayed" BM harvest for allogeneic transplantation. Five normal donors received G-CSF @ 10 mcg/kg/day x 5 followed by repeat PB and BM assays at day 6 and 16, and BM harvest at day 16. Stem cells were not increased in the BM at day 16. Five patients underwent BMT and engrafted at +10 to +19 days. While the tested strategy offers no intrinsic advantages, its potential cannot be evaluated fully without alternative timing and/or additional, "early acting" growth factors.

UV-enhanced reactivation in mammalian cells: increase by caffeine

International Nuclear Information System (INIS)

Lytle, C.D.; Iacangelo, A.L.; Lin, C.H.; Goddard, J.G.

1981-01-01

It has been reported that caffeine decreases UV-enhanced reactivation of UV-irradiated Herpes simplex virus in CV-l monkey kidney cells. That occurred when there was no delay between cell irradiation and virus infection. In the present study, virus infection was delayed following cell irradiation to allow an 'induction' period separate from the 'expression' period which occurs during the virus infection. Thus, the effects of caffeine on 'induction' and 'expression' could be determined separately. Caffeine increased the expression of UV-enhanced reactivation, while causing a small decrease in the 'induction' of enhanced reactivation. (author)

In vivo stem cell function of interleukin-3-induced blast cells

International Nuclear Information System (INIS)

Tsunoda, J.; Okada, S.; Suda, J.; Nagayoshi, K.; Nakauchi, H.; Hatake, K.; Miura, Y.; Suda, T.

1991-01-01

The treatment of mice with high doses of 5-fluorouracil (5-FU) results in an enrichment of primitive hematopoietic progenitors. Using this procedure, the authors obtained a new class of murine hematopoietic colonies that had very high secondary plating efficiencies in vitro and could differentiate into not only myeloid cells but also into lymphoid lineage cells. The phenotypes of interleukin-3 (IL-3) induced blast colony cells were Thy-1-positive and lineage-marker-negative. They examined whether these blast colony cells contained primitive hematopoietic stem cells in vivo and could reconstitute hematopoietic tissues in lethally irradiated mice. Blast colony cells could generate macroscopic visible spleen colonies on days 8 and 12, and 5 x 10(3) blast cells were sufficient to protect them from lethally irradiation. It was shown that 6 or 8 weeks after transplantation of 5 x 10(3) blast cells, donor male cells were detected in the spleen and thymus of the female recipients but not in the bone marrow by Southern blot analysis using Y-encoded DNA probe. After 10 weeks, bone marrow cells were partially repopulated from donor cells. In a congenic mouse system, donor-derived cells (Ly5.2) were detected in the thymus and spleen 6 weeks after transplantation. Fluorescence-activated cell sorter analyses showed that B cells and macrophages developed from donor cells in the spleen. In the thymus, donor-derived cells were found in CD4, CD8 double-positive, single-positive, and double-negative populations. Reconstitution of bone marrow was delayed and myeloid and lymphoid cells were detected 10 weeks after transplantation. These results indicate that IL-3-induced blast cells contain the primitive hematopoietic stem cells capable of reconstituting hematopoietic organs in lethally irradiated mice

Autologous neural progenitor cell transplantation into newborn mice modeling for E200K genetic prion disease delays disease progression.

Science.gov (United States)

Frid, Kati; Binyamin, Orli; Fainstein, Nina; Keller, Guy; Ben-Hur, Tamir; Gabizon, Ruth

2018-05-01

TgMHu2ME199K mice, a transgenic line mimicking genetic prion disease, are born healthy and gradually deteriorate to a terminal neurological condition concomitant with the accumulation of disease-related PrP. To investigate whether transplantation of neural progenitor cells (NPCs) to these mice can delay disease aggravation, we first tested the properties of mutant PrP in homogenates and enriched NPCs from TgMHu2ME199K embryos, as compared to PrP in sick TgMHu2ME199K brains. Next, we tested the clinical effect of NPCs transplantation into newborn TgMHu2ME199K mice. We show that mutant PrP does not convert into a disease-related isoform while in progenitor cells. Most important, transplantation of both wild type and transgenic NPCs significantly delayed the progression of spontaneous prion disease in TgMHu2ME199K mice. While the strong clinical effect was not accompanied by a reduced accumulation of disease-related PrP, treated mouse brains presented a significant reduction in amyloid glycosaminoglycans and preservation of neurogenesis levels, indicating a strong neuroprotective effect. These results may encourage the investigation of new pathways for treatment in these terrible diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

Survival and kinetics of Chinese hamster ovary cell subpopulations induced by Adriamycin and radiation

International Nuclear Information System (INIS)

Schneiderman, M.H.

1979-01-01

Mitotic selection of Chinese hamster ovary (CHO) cells, at 10 min intervals after the initiation of Adriamycin and/or x-ray treatment was used to measure the kinetics and survival of cells which progressed without delay, the ''refractory'' cells, the cells that reached mitosis only after recovery from the treatment-induced delay, the ''recovered'' cells, and the survival of the cells remaining attached to the flask 5 h after treatment. The cell kinetics were determined from the rate at which cells entered mitosis, and the reproductive integrity from the survival of the selected refractory, recovered and remaining (unselected) cells

The hematopoietic chemokine CXCL12 promotes integration of human endothelial colony forming cell-derived cells into immature vessel networks.

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Newey, Sarah E; Tsaknakis, Grigorios; Khoo, Cheen P; Athanassopoulos, Thanassi; Camicia, Rosalba; Zhang, Youyi; Grabowska, Rita; Harris, Adrian L; Roubelakis, Maria G; Watt, Suzanne M

2014-11-15

Proangiogenic factors, vascular endothelial growth factor (VEGF), and fibroblast growth factor-2 (FGF-2) prime endothelial cells to respond to "hematopoietic" chemokines and cytokines by inducing/upregulating expression of the respective chemokine/cytokine receptors. Coculture of human endothelial colony forming cell (ECFC)-derived cells with human stromal cells in the presence of VEGF and FGF-2 for 14 days resulted in upregulation of the "hematopoietic" chemokine CXCL12 and its CXCR4 receptor by day 3 of coculture. Chronic exposure to the CXCR4 antagonist AMD3100 in this vasculo/angiogenesis assay significantly reduced vascular tubule formation, an observation recapitulated by delayed AMD3100 addition. While AMD3100 did not affect ECFC-derived cell proliferation, it did demonstrate a dual action. First, over the later stages of the 14-day cocultures, AMD3100 delayed tubule organization into maturing vessel networks, resulting in enhanced endothelial cell retraction and loss of complexity as defined by live cell imaging. Second, at earlier stages of cocultures, we observed that AMD3100 significantly inhibited the integration of exogenous ECFC-derived cells into established, but immature, vascular networks. Comparative proteome profiler array analyses of ECFC-derived cells treated with AMD3100 identified changes in expression of potential candidate molecules involved in adhesion and/or migration. Blocking antibodies to CD31, but not CD146 or CD166, reduced the ECFC-derived cell integration into these extant vascular networks. Thus, CXCL12 plays a key role not only in endothelial cell sensing and guidance, but also in promoting the integration of ECFC-derived cells into developing vascular networks.

Modeling the Effects of Vorinostat In Vivo Reveals both Transient and Delayed HIV Transcriptional Activation and Minimal Killing of Latently Infected Cells.

Science.gov (United States)

Ke, Ruian; Lewin, Sharon R; Elliott, Julian H; Perelson, Alan S

2015-10-01

Recent efforts to cure human immunodeficiency virus type-1 (HIV-1) infection have focused on developing latency reversing agents as a first step to eradicate the latent reservoir. The histone deacetylase inhibitor, vorinostat, has been shown to activate HIV RNA transcription in CD4+ T-cells and alter host cell gene transcription in HIV-infected individuals on antiretroviral therapy. In order to understand how latently infected cells respond dynamically to vorinostat treatment and determine the impact of vorinostat on reservoir size in vivo, we have constructed viral dynamic models of latency that incorporate vorinostat treatment. We fitted these models to data collected from a recent clinical trial in which vorinostat was administered daily for 14 days to HIV-infected individuals on suppressive ART. The results show that HIV transcription is increased transiently during the first few hours or days of treatment and that there is a delay before a sustained increase of HIV transcription, whose duration varies among study participants and may depend on the long term impact of vorinostat on host gene expression. Parameter estimation suggests that in latently infected cells, HIV transcription induced by vorinostat occurs at lower levels than in productively infected cells. Furthermore, the estimated loss rate of transcriptionally induced cells remains close to baseline in most study participants, suggesting vorinostat treatment does not induce latently infected cell killing and thus reduce the latent reservoir in vivo.

Natural killer cells in leukemogenesis

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Seidel, H.J.; Stolz, W.; Sutter, H.; Kreja, L.

1986-01-01

In order to relate a reduced natural killer (NK) cell function to leukemogenesis, NK cells in the spleen and peritoneal exudate cells, with and without stimulation by Corynebacterium parvum, were tested in mice of various strains after split dose irradiation and after leukemogenic treatment with butyl- and methylnitrosourea. The investigations included also mice submitted to non-leukemogenic irradiation (1 x 1.5 and 1 x 4.5 Gy) and mice submitted to an additional treatment with hydrocortisone, which delays leukemia development after methylnitrosourea. There was, indeed, a NK-cell depression, but no major differences were seen between mice prone to leukemia development and those after cytotoxic, but nonleukemogenic, treatment.

Death receptor pathways mediate targeted and non-targeted effects of ionizing radiations in breast cancer cells

International Nuclear Information System (INIS)

Luce, A.; Courtin, A.; Levalois, C.; Altmeyer-Morel, S.; Chevillard, S.; Lebeau, J.; Romeo, P.H.

2009-01-01

Delayed cell death by mitotic catastrophe is a frequent mode of solid tumor cell death after γ-irradiation, a widely used treatment of cancer. Whereas the mechanisms that underlie the early γ-irradiation-induced cell death are well documented, those that drive the delayed cell death are largely unknown. Here we show that the Fas, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and tumor necrosis factor (TNF)-α death receptor pathways mediate the delayed cell death observed after γ-irradiation of breast cancer cells. Early after irradiation, we observe the increased expression of Fas, TRAIL-R and TNF-R that first sensitizes cells to apoptosis. Later, the increased expression of FasL, TRAIL and TNF-α permit the apoptosis engagement linked to mitotic catastrophe. Treatments with TNF-α, TRAIL or anti-Fas antibody, early after radiation exposure, induce apoptosis, whereas the neutralization of the three death receptors pathways impairs the delayed cell death. We also show for the first time that irradiated breast cancer cells excrete soluble forms of the three ligands that can induce the death of sensitive bystander cells. Overall, these results define the molecular basis of the delayed cell death of irradiated cancer cells and identify the death receptors pathways as crucial actors in apoptosis induced by targeted as well as non-targeted effects of ionizing radiation. (authors)

Decitabine induces delayed reactive oxygen species (ROS) accumulation in leukemia cells and induces the expression of ROS generating enzymes.

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Fandy, Tamer E; Jiemjit, Anchalee; Thakar, Manjusha; Rhoden, Paulette; Suarez, Lauren; Gore, Steven D

2014-03-01

Azanucleoside DNA methyltransferase (DNMT) inhibitors are currently approved by the U.S. Food and Drug Administration for treatment of myelodysplastic syndrome. The relative contributions of DNMT inhibition and other off-target effects to their clinical efficacy remain unclear. Data correlating DNA methylation reversal and clinical response have been conflicting. Consequently, it is necessary to investigate so-called off-target effects and their impact on cell survival and differentiation. Flow cytometry was used for cell cycle, apoptosis, and reactive oxygen species (ROS) accumulation analysis. Gene expression analysis was performed using real-time PCR. DNA methylation was detected by methylation-specific PCR. Mitochondrial membrane potential was analyzed using JC-1 dye staining. Western blotting was used for quantitative protein expression analysis. 5-Aza-2'-deoxycytidine (DAC) induced cell-cycle arrest and apoptosis in leukemia cells. p53 expression was dispensable for DAC-induced apoptosis. DAC induced delayed ROS accumulation in leukemia cells but not in solid tumor cells and p53 expression was dispensable for ROS increase. ROS increase was deoxycytidine kinase dependent, indicating that incorporation of DAC into nuclear DNA is required for ROS generation. ROS accumulation by DAC was caspase-independent and mediated the dissipation of the mitochondrial membrane potential. Concordantly, ROS scavengers diminished DAC-induced apoptosis. DAC induced the expression of different NADPH oxidase isoforms and upregulated Nox4 protein expression in an ATM-dependent manner, indicating the involvement of DNA damage signaling in Nox4 upregulation. These data highlight the importance of mechanisms other than DNA cytosine demethylation in modulating gene expression and suggest investigating the relevance of ROS accumulation to the clinical activity of DAC. ©2014 AACR

Effects of bleomycin and irradiation on euoxic and hypoxic cells

International Nuclear Information System (INIS)

Shrieve, D.C.; Harris, J.W.

1979-01-01

EMT6 cells in vitro were exposed to bleomycin (BLM), either alone (under euoxic or hypoxic conditions) or in conjunction with x-radiation. Hypoxic and euoxic cells were equally sensitive to the drug in both of the systems used to induce hypoxia (ampules or chambers). Exposure to BLM immediately before x-irradiation altered the shape of the radiation survival curve decreasing the D 0 by a factor of 1.3. Simultaneous exposure to x-ray and BLM resulted in lower survivals than when radiation was given either before or after drug treatment. Cells recovered quickly from BLM damage if trypsinization was delayed. The results indicate that BLM and x-rays interact to lower cell survival but that cells recover from this effect if trypsinization is delayed

Live-cell imaging study of mitochondrial morphology in mammalian cells exposed to X-rays

International Nuclear Information System (INIS)

Noguchi, M.; Yokoya, A.; Narita, A.; Fujii, K.; Kanari, Y.

2015-01-01

Morphological changes in mitochondria induced by X-irradiation in normal murine mammary gland cells were studied with a live-cell microscopic imaging technique. Mitochondria were visualised by staining with a specific fluorescent probe in the cells, which express fluorescent ubiquitination-based cell-cycle indicator 2 (Fucci2) probes to visualise cell cycle. In unirradiated cells, the number of cells with fragmented mitochondria was about 20 % of the total cells through observation period (96 h). In irradiated cells, the population with fragmented mitochondria significantly increased depending on the absorbed dose. Particularly, for 8 Gy irradiation, the accumulation of fragmentation persists even in the cells whose cell cycle came to a stand (80 % in G1 (G0-like) phase). The fraction reached to a maximum at 96 h after irradiation. The kinetics of the fraction with fragmented mitochondria was similar to that for cells in S/G2/M phase (20 %) through the observation period (120 h). The evidences show that, in irradiated cells, some signals are continually released from a nucleus or cytoplasm even in the G0-like cells to operate some sort of protein machineries involved in mitochondrial fission. It is inferred that this delayed mitochondrial fragmentation is strongly related to their dysfunction, and hence might modulate radiobiological effects such as mutation or cell death. (authors)

Characterization of a serine protease-mediated cell death program activated in human leukemia cells

International Nuclear Information System (INIS)

O'Connell, A.R.; Holohan, C.; Torriglia, A.; Lee, B.F.; Stenson-Cox, C.

2006-01-01

Tightly controlled proteolysis is a defining feature of apoptosis and caspases are critical in this regard. Significant roles for non-caspase proteases in cell death have been highlighted. Staurosporine causes a rapid induction of apoptosis in virtually all mammalian cell types. Numerous studies demonstrate that staurosporine can activate cell death under caspase-inhibiting circumstances. The aim of this study was to investigate the proteolytic mechanisms responsible for cell death under these conditions. To that end, we show that inhibitors of serine proteases can delay cell death in one such system. Furthermore, through profiling of proteolytic activation, we demonstrate, for the first time, that staurosporine activates a chymotrypsin-like serine protease-dependent cell death in HL-60 cells independently, but in parallel with the caspase controlled systems. Features of the serine protease-mediated system include cell shrinkage and apoptotic morphology, regulation of caspase-3, altered nuclear morphology, generation of an endonuclease and DNA degradation. We also demonstrate a staurosporine-induced activation of a putative 16 kDa chymotrypsin-like protein during apoptosis

Subretinally transplanted embryonic stem cells rescue photoreceptor cells from degeneration in the RCS rats.

Science.gov (United States)

Schraermeyer, U; Thumann, G; Luther, T; Kociok, N; Armhold, S; Kruttwig, K; Andressen, C; Addicks, K; Bartz-Schmidt, K U

2001-01-01

The Royal College of Surgeons (RCS) rat is an animal model for retinal degeneration such as the age-related macular degeneration. The RCS rat undergoes a progressive retinal degeneration during the early postnatal period. A potential treatment to prevent this retinal degeneration is the transplantation into the subretinal space of cells that would replace functions of the degenerating retinal pigment epithelium (RPE) cells or may form neurotrophic factors. In this study we have investigated the potential of subretinally transplanted embryonic stem cells to prevent the genetically determined photoreceptor cell degeneration in the RCS rat. Embryonic stem cells from the inner cell mass of the mouse blastocyst were allowed to differentiate to neural precursor cells in vitro and were then transplanted into the subretinal space of 20-day-old RCS rats. Transplanted and sham-operated rats were sacrificed 2 months following cell transplantation. The eyes were enucleated and photoreceptor degeneration was quantified by analyzing and determining the thickness of the outer nuclear layer by light and electron microscopy. In the eyes transplanted with embryonic cells up to 8 rows of photoreceptor cell nuclei were observed, whereas in nontreated control eyes the outer nuclear layer had degenerated completely. Transplantation of embryonic stem cells appears to delay photoreceptor cell degeneration in RCS rats.

Sensitization by wortmannin of heat- or X-ray induced cell death in cultured Chinese hamster V79 cells

International Nuclear Information System (INIS)

Tomita, Masanori; Suzuki, Norio; Matsumoto, Yoshihisa; Hirano, Kazuya; Umeda, Noriko; Sakai, Kazuo

2000-01-01

Here we found that wortmannin sensitized Chinese hamster V79 cells to hyperthermic treatment at 44.0 deg C as determined either by colony formation assay or by dye exclusion assay. Wortmannin enhanced heat-induced cell death accompanying cleavage of poly (ADP-ribose) polymerases (PARP). Additionally, the induction of heat shock protein HSP70 was suppressed and delayed in wortmannin-treated cells. Heat sensitizing effect of wortmannin was obvious at more than 5 or 10 μM of final concentrations, while radiosensitization was apparent at 5 μM. Requirement for high concentration of wortmannin, i.e., order of μM, suggests a possible role of certain protein kinases, such as DNA-PK and/or ATM among PI3-kinase family. The sensitization was minimal when wortmannin was added at the end of heat treatment. This was similar to the case of X-ray. Since heat-induced cell death and PARP cleavage preceded HSP70 induction phenomenon, the sensitization to the hyperthermic treatment was considered mainly caused by enhanced apoptotic cell death rather than secondary to suppression or delay by wortmannin of HSP70 induction. Further, in the present system radiosensitization by wortmannin was also at least partly mediated through enhancement of apoptotic cell death. (author)

Role of whole bone marrow, whole bone marrow cultured cells, and mesenchymal stem cells in chronic wound healing.

Science.gov (United States)

Rodriguez-Menocal, Luis; Shareef, Shahjahan; Salgado, Marcela; Shabbir, Arsalan; Van Badiavas, Evangelos

2015-03-13

Recent evidence has shown that bone marrow cells play critical roles during the inflammatory, proliferative and remodeling phases of cutaneous wound healing. Among the bone marrow cells delivered to wounds are stem cells, which can differentiate into multiple tissue-forming cell lineages to effect, healing. Gaining insight into which lineages are most important in accelerating wound healing would be quite valuable in designing therapeutic approaches for difficult to heal wounds. In this report we compared the effect of different bone marrow preparations on established in vitro wound healing assays. The preparations examined were whole bone marrow (WBM), whole bone marrow (long term initiating/hematopoietic based) cultured cells (BMC), and bone marrow derived mesenchymal stem cells (BM-MSC). We also applied these bone marrow preparations in two murine models of radiation induced delayed wound healing to determine which had a greater effect on healing. Angiogenesis assays demonstrated that tube formation was stimulated by both WBM and BMC, with WBM having the greatest effect. Scratch wound assays showed higher fibroblast migration at 24, 48, and 72 hours in presence of WBM as compared to BM-MSC. WBM also appeared to stimulate a greater healing response than BMC and BM-MSC in a radiation induced delayed wound healing animal model. These studies promise to help elucidate the role of stem cells during repair of chronic wounds and reveal which cells present in bone marrow might contribute most to the wound healing process.

Cell of Origin and Cancer Stem Cells in Tumor Suppressor Mouse Models of Glioblastoma.

Science.gov (United States)

Alcantara Llaguno, Sheila R; Xie, Xuanhua; Parada, Luis F

2016-01-01

The cellular origins and the mechanisms of progression, maintenance of tumorigenicity, and therapeutic resistance are central questions in the glioblastoma multiforme (GBM) field. Using tumor suppressor mouse models, our group recently reported two independent populations of adult GBM-initiating central nervous system progenitors. We found different functional and molecular subtypes depending on the tumor-initiating cell lineage, indicating that the cell of origin is a driver of GBM subtype diversity. Using an in vivo model, we also showed that GBM cancer stem cells (CSCs) or glioma stem cells (GSCs) contribute to resistance to chemotherapeutic agents and that genetic ablation of GSCs leads to a delay in tumor progression. These studies are consistent with the cell of origin and CSCs as critical regulators of the pathogenesis of GBM. © 2016 Alcantara Llaguno et al; Published by Cold Spring Harbor Laboratory Press.

Impact of blood processing variations on Natural Killer cell frequency, activation, chemokine receptor expression and function

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Naranbhai, Vivek; Bartman, Pat; Ndlovu, Dudu; Ramkalawon, Pamela; Ndung’u, Thumbi; Wilson, Douglas; Altfeld, Marcus; Carr, William H

2011-01-01

Understanding the role of natural killer (NK) cells in human disease pathogenesis is crucial and necessitates study of patient samples directly ex vivo. Manipulation of whole blood by density gradient centrifugation or delays in sample processing due to shipping, however, may lead to artifactual changes in immune response measures. Here, we assessed the impact of density gradient centrifugation and delayed processing of both whole blood and peripheral blood mononuclear cells (PBMC) at multiple timepoints (2–24 hrs) on flow cytometric measures of NK cell frequency, activation status, chemokine receptor expression, and effector functions. We found that density gradient centrifugation activated NK cells and modified chemokine receptor expression. Delays in processing beyond 8 hours activated NK cells in PBMC but not in whole blood. Likewise, processing delays decreased chemokine receptor (CCR4 and CCR7) expression in both PBMC and whole blood. Finally, delays in processing PBMC were associated with a decreased ability of NK cells to degranulate (as measured by CD107a expression) or secrete cytokines (IFN-γ and TNF-α). In summary, our findings suggest that density gradient centrifugation and delayed processing of PBMC can alter measures of clinically relevant NK cell characteristics including effector functions; and therefore should be taken into account in designing clinical research studies. PMID:21255578

Natural Killer Cells Improve Hematopoietic Stem Cell Engraftment by Increasing Stem Cell Clonogenicity In Vitro and in a Humanized Mouse Model.

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Escobedo-Cousin, Michelle; Jackson, Nicola; Laza-Briviesca, Raquel; Ariza-McNaughton, Linda; Luevano, Martha; Derniame, Sophie; Querol, Sergio; Blundell, Michael; Thrasher, Adrian; Soria, Bernat; Cooper, Nichola; Bonnet, Dominique; Madrigal, Alejandro; Saudemont, Aurore

2015-01-01

Cord blood (CB) is increasingly used as a source of hematopoietic stem cells (HSC) for transplantation. Low incidence and severity of graft-versus-host disease (GvHD) and a robust graft-versus-leukemia (GvL) effect are observed following CB transplantation (CBT). However, its main disadvantages are a limited number of HSC per unit, delayed immune reconstitution and a higher incidence of infection. Unmanipulated grafts contain accessory cells that may facilitate HSC engraftment. Therefore, the effects of accessory cells, particularly natural killer (NK) cells, on human CB HSC (CBSC) functions were assessed in vitro and in vivo. CBSC cultured with autologous CB NK cells showed higher levels of CXCR4 expression, a higher migration index and a higher number of colony forming units (CFU) after short-term and long-term cultures. We found that CBSC secreted CXCL9 following interaction with CB NK cells. In addition, recombinant CXCL9 increased CBSC clonogenicity, recapitulating the effect observed of CB NK cells on CBSC. Moreover, the co-infusion of CBSC with CB NK cells led to a higher level of CBSC engraftment in NSG mouse model. The results presented in this work offer the basis for an alternative approach to enhance HSC engraftment that could improve the outcome of CBT.

Secondary immunization generates clonally related antigen-specific plasma cells and memory B cells.

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Frölich, Daniela; Giesecke, Claudia; Mei, Henrik E; Reiter, Karin; Daridon, Capucine; Lipsky, Peter E; Dörner, Thomas

2010-09-01

Rechallenge with T cell-dependent Ags induces memory B cells to re-enter germinal centers (GCs) and undergo further expansion and differentiation into plasma cells (PCs) and secondary memory B cells. It is currently not known whether the expanded population of memory B cells and PCs generated in secondary GCs are clonally related, nor has the extent of proliferation and somatic hypermutation of their precursors been delineated. In this study, after secondary tetanus toxoid (TT) immunization, TT-specific PCs increased 17- to 80-fold on days 6-7, whereas TT-specific memory B cells peaked (delayed) on day 14 with a 2- to 22-fold increase. Molecular analyses of V(H)DJ(H) rearrangements of individual cells revealed no major differences of gene usage and CDR3 length between TT-specific PCs and memory B cells, and both contained extensive evidence of somatic hypermutation with a pattern consistent with GC reactions. This analysis identified clonally related TT-specific memory B cells and PCs. Within clusters of clonally related cells, sequences shared a number of mutations but also could contain additional base pair changes. The data indicate that although following secondary immunization PCs can derive from memory B cells without further somatic hypermutation, in some circumstances, likely within GC reactions, asymmetric mutation can occur. These results suggest that after the fate decision to differentiate into secondary memory B cells or PCs, some committed precursors continue to proliferate and mutate their V(H) genes.

Delayed expression of cell cycle proteins contributes to astroglial scar formation and chronic inflammation after rat spinal cord contusion

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Wu Junfang

2012-07-01

Full Text Available Abstract Background Traumatic spinal cord injury (SCI induces secondary tissue damage that is associated with astrogliosis and inflammation. We previously reported that acute upregulation of a cluster of cell-cycle-related genes contributes to post-mitotic cell death and secondary damage after SCI. However, it remains unclear whether cell cycle activation continues more chronically and contributes to more delayed glial change. Here we examined expression of cell cycle-related proteins up to 4 months following SCI, as well as the effects of the selective cyclin-dependent kinase (CDKs inhibitor CR8, on astrogliosis and microglial activation in a rat SCI contusion model. Methods Adult male rats were subjected to moderate spinal cord contusion injury at T8 using a well-characterized weight-drop model. Tissue from the lesion epicenter was obtained 4 weeks or 4 months post-injury, and processed for protein expression and lesion volume. Functional recovery was assessed over the 4 months after injury. Results Immunoblot analysis demonstrated a marked continued upregulation of cell cycle-related proteins − including cyclin D1 and E, CDK4, E2F5 and PCNA − for 4 months post-injury that were highly expressed by GFAP+ astrocytes and microglia, and co-localized with inflammatory-related proteins. CR8 administrated systemically 3 h post-injury and continued for 7 days limited the sustained elevation of cell cycle proteins and immunoreactivity of GFAP, Iba-1 and p22PHOX − a key component of NADPH oxidase − up to 4 months after SCI. CR8 treatment significantly reduced lesion volume, which typically progressed in untreated animals between 1 and 4 months after trauma. Functional recovery was also significantly improved by CR8 treatment after SCI from week 2 through week 16. Conclusions These data demonstrate that cell cycle-related proteins are chronically upregulated after SCI and may contribute to astroglial scar

Selective induction of cyclin B protein abrogates the G2 delay after irradiation

International Nuclear Information System (INIS)

Kao, G.; Muschel, R.J.; Maity, A.; Kunig, A.; McKenna, W.G.

1996-01-01

Purpose/Objective: Irradiation of tumor cells commonly results in G2 delay, which has been postulated to allow DNA repair and cell survival. The G2 delay after irradiation is also often marked in some cell lines by delayed expression of cyclin B protein, suggesting a role for cyclin B regulation. Investigations of these hypotheses however has been hampered by the inability to selectively perturb the G2 delay in a physiologic manner. Materials and Methods: We have devised a system, with which we are able to selectively induce cyclin B protein expression in vivo at specific points in the cell cycle, by transfecting Hela cells with an expression vector under control of a dexamethasone-inducible promoter. Experiments were subsequently performed by synchronizing, releasing, irradiating, inducing, and harvesting these cells through the cell cycle. Results: Irradiation with 5 Gy led to a pronounced G2 delay, reflected by markedly slowed progression into mitosis, concomitant with reduced expression of cyclin B protein. Induction of cyclin B after radiation in these cells abrogated the G2 delay by approximately doubling the rate at which the cells re-enter mitosis. Treatment of irradiated untransfected control cells with dexamethasone, in which cyclin B is not induced, led to minimal changes. Studies of effects of cyclin B induction on cyclin B localization (using immunofluorescence), cdc2 phosphorylation and activation will also be presented. Conclusion: This system should allow further investigations into fundamental mechanisms of cell cycle regulation after irradiation and DNA damage. This also provides direct evidence for the first time that cyclin B protein regulation may play a role in the G2 delay following irradiation in Hela cells, perhaps complementing phosphorylation events

Cell-cycle-dependent repair of heavy-ion damage

International Nuclear Information System (INIS)

Blakely, E.A.; Chang, P.Y.; Lommel, L.; Tobias, C.A.

1985-01-01

Synchronized human T-1 cells have been used to investigate the G1-phase age dependence of repair of potentially lethal damage (PLDR). The cells were irradiated with single doses of either 225 kVp X rays or Bragg-peak 425 MeV/μ neon ions at ages between 1.5 and 6.0 hrs after mitotic selection, and then either trypsinized and plated immediately, or held at 37 0 C for 6 hrs in PBS, or PBS containing 60μM of the DNA-polymerase-inhibitor 1-β-D-arabinofurano-syladenine (β-araA) before trypsinization and plating. Delayed plating showed significant PLDR at all ages irradiated with X rays, with the increase of survival varying between 2- to 8-fold. At equivalent survival levels, there was a reduced capacity for PLDT at each cell age irradiated with neon ions. In early G1 after neon-ion exposures, delayed plating actually enhanced cell killing; whereas, in late G1 the survival increased about 2-fold. β-araA almost completely eliminated the PLDR after X rays, reducing the survival to that measured with immediate plating. β-araA slightly enhanced neon-ion cell killing at all cell ages

Radiation response of mouse lymphoid and myeloid cell lines. Pt. 3

International Nuclear Information System (INIS)

Radford, I.R.; Murphy, T.K.

1994-01-01

The authors have examined the timing of γ-irradiation-induced death in relation to cell cycle progression using a panel of mouse lymphoid or myeloid cell lines. Death was found to occur immediately after irradiation ('rapid interphase' death), or after arrest in G 2 phase ('delayed interphase' death), or following one or more mitoses ('mitotic/delayed mitotic' death). In part II of this series of papers the authors demonstrated the occurrence of radiation-induced apoptosis in all these cell lines. Several of the cell lines showed different timing of death dependent upon the radiation dose used. These differences in the timing of radiation-induced death are shown to be useful indicators of the relative radiosensitivity of haematopoietic cell lines. (author)

Functional dysregulation of stem cells during aging: a focus on skeletal muscle stem cells.

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García-Prat, Laura; Sousa-Victor, Pedro; Muñoz-Cánoves, Pura

2013-09-01

Aging of an organism is associated with the functional decline of tissues and organs, as well as a sharp decline in the regenerative capacity of stem cells. A prevailing view holds that the aging rate of an individual depends on the ratio of tissue attrition to tissue regeneration. Therefore, manipulations that favor the balance towards regeneration may prevent or delay aging. Skeletal muscle is a specialized tissue composed of postmitotic myofibers that contract to generate force. Satellite cells are the adult stem cells responsible for skeletal muscle regeneration. Recent studies on the biology of skeletal muscle and satellite cells in aging have uncovered the critical impact of systemic and niche factors on stem cell functionality and demonstrated the capacity of aged satellite cells to rejuvenate and increase their regenerative potential when exposed to a youthful environment. Here we review the current literature on the coordinated relationship between cell extrinsic and intrinsic factors that regulate the function of satellite cells, and ultimately determine tissue homeostasis and repair during aging, and which encourage the search for new anti-aging strategies. © 2013 The Authors Journal compilation © 2013 FEBS.

Low dose ultraviolet B-irradiated Langerhans cells preferentially activate CD4+ cells of the T helper 2 subset

International Nuclear Information System (INIS)

Simon, J.C.; Cruz, P.D. Jr.; Bergstresser, P.R.; Tigelaar, R.E.

1990-01-01

UVB radiation distorts the Ag-presenting function of epidermal Langerhans cells (LC); this has been shown for the presentation of soluble Ag to primed T cells in vitro and for the initiation of delayed-type hypersensitivity in vivo, such as contact hypersensitivity (CH). Previous work has also demonstrated UVB-induced suppression of CH to be mediated ultimately by T cells. Two subsets of CD4+ Th cells, Th1 and Th2, have been identified, based on their cytokine production and functional activities. In particular, Th1 mediate delayed-type hypersensitivity, whereas Th2 do not. To investigate whether the perturbation of LC function induced by UVB radiation leads to a differential activation of these subsets of CD4+ cells, we examined the capacity of unirradiated and irradiated (200 J/m2) APC from adult BALB/c mice to present keyhole limpet hemocyanin to Ag-specific, H2d-restricted Th1 and Th2 cell lines. Four sources of APC were utilized: epidermal cells (EC), flow microfluorometry-purified Ia+ EC (LC), flow microfluorometry-purified Ia- EC, and splenic adherent cells (SAC). Unirradiated EC, LC, and SAC, but not Ia-EC, presented keyhole limpet hemocyanin to both Th1 and Th2. Irradiated EC and LC lost their ability to stimulate Th1, but retained fully their capacity to stimulate Th2. On the other hand, irradiated SAC were unable to induce proliferation of either Th1 or Th2. These findings indicate that suppression of CH mediated by UVB-irradiated LC may result from an alteration of the ratio and/or activity of Th1 and Th2 cells normally generated during the induction of such responses

Selective T-cell depletion targeting CD45RA reduces viremia and enhances early T-cell recovery compared with CD3-targeted T-cell depletion.

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Triplett, Brandon M; Muller, Brad; Kang, Guolian; Li, Ying; Cross, Shane J; Moen, Joseph; Cunningham, Lea; Janssen, William; Mamcarz, Ewelina; Shook, David R; Srinivasan, Ashok; Choi, John; Hayden, Randall T; Leung, Wing

2018-02-01

T-cell depletion (TCD) effectively reduces severe graft-versus-host disease in recipients of HLA-mismatched allografts. However, TCD is associated with delayed immune recovery and increased infections. We hypothesized that specific depletion of CD45RA+ naive T cells, rather than broad depletion of CD3+ T cells, can preserve memory-immunity in the allografts and confer protection against important viral infections in the early post-transplant period. Sixty-seven patients who received TCD haploidentical donor transplantation for hematologic malignancy on 3 consecutive trials were analyzed. Patients receiving CD45RA-depleted donor grafts had 2000-fold more donor T cells infused, significantly higher T-cell counts at Day +30 post transplant (550/μL vs 10/μL; P depleted grafts were more likely to experience adenovirus viremia (27% vs 4%, P = .02). CD45RA-depletion provided a large number of donor memory T cells to the recipients and was associated with enhanced early T-cell recovery and protection against viremia. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Radiation induced processes in moss cells

International Nuclear Information System (INIS)

Doehren, R. v.

1975-01-01

The moss F.h. shows apical growth in the protonema cells which spread radially from the spor. Every apical daughter cell during the state of 'Caulonema' and just before in the state of 'Caulonema Primanen' initiates cell division as soon as more than twice the length of the mother cell is reached. All this allows to follow radiation effects in single cells conveniently. UV irradiation on the range of 254 nm and 280 nm delivered at different parts of the cell area delays cell division markedly may suppress it, and is able to stop the process of growing in relation to the delivered dose and to the irradiated area as well. In case of irradiation of the area next to where the membrane is just being formed - that is to say next to the phragmoplast - the new membrane will be wrongly oriented. In particular giant cells are occurring in the case of nucleus irradiation during early prophase. (orig./GSE) [de

Adipose-derived stromal cells inhibit prostate cancer cell proliferation inducing apoptosis

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Takahara, Kiyoshi [Department of Urology, Faculty of Medicine, Osaka Medical College, Osaka (Japan); Ii, Masaaki, E-mail: masaii@art.osaka-med.ac.jp [Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Osaka (Japan); Inamoto, Teruo; Komura, Kazumasa; Ibuki, Naokazu; Minami, Koichiro; Uehara, Hirofumi; Hirano, Hajime; Nomi, Hayahito; Kiyama, Satoshi [Department of Urology, Faculty of Medicine, Osaka Medical College, Osaka (Japan); Asahi, Michio [Department of Pharmacology, Faculty of Medicine, Osaka Medical College, Osaka (Japan); Azuma, Haruhito [Department of Urology, Faculty of Medicine, Osaka Medical College, Osaka (Japan)

2014-04-18

Highlights: • AdSC transplantation exhibits inhibitory effect on tumor progressions of PCa cells. • AdSC-induced PCa cell apoptosis may occur via the TGF-β signaling pathway. • High expression of the TGF-β1 gene in AdSCs. - Abstract: Mesenchymal stem cells (MSCs) have generated a great deal of interest in the field of regenerative medicine. Adipose-derived stromal cells (AdSCs) are known to exhibit extensive proliferation potential and can undergo multilineage differentiation, sharing similar characteristics to bone marrow-derived MSCs. However, as the effect of AdSCs on tumor growth has not been studied sufficiently, we assessed the degree to which AdSCs affect the proliferation of prostate cancer (PCa) cell. Human AdSCs exerted an inhibitory effect on the proliferation of androgen-responsive (LNCaP) and androgen-nonresponsive (PC3) human PCa cells, while normal human dermal fibroblasts (NHDFs) did not, and in fact promoted PCa cell proliferation to a degree. Moreover, AdSCs induced apoptosis of LNCaP cells and PC3 cells, activating the caspase3/7 signaling pathway. cDNA microarray analysis suggested that AdSC-induced apoptosis in both LNCaP and PC3 cells was related to the TGF-β signaling pathway. Consistent with our in vitro observations, local transplantation of AdSCs delayed the growth of tumors derived from both LNCaP- and PC3-xenografts in immunodeficient mice. This is the first preclinical study to have directly demonstrated that AdSC-induced PCa cell apoptosis may occur via the TGF-β signaling pathway, irrespective of androgen-responsiveness. Since autologous AdSCs can be easily isolated from adipose tissue without any ethical concerns, we suggest that therapy with these cells could be a novel approach for patients with PCa.

Adipose-derived stromal cells inhibit prostate cancer cell proliferation inducing apoptosis

International Nuclear Information System (INIS)

Takahara, Kiyoshi; Ii, Masaaki; Inamoto, Teruo; Komura, Kazumasa; Ibuki, Naokazu; Minami, Koichiro; Uehara, Hirofumi; Hirano, Hajime; Nomi, Hayahito; Kiyama, Satoshi; Asahi, Michio; Azuma, Haruhito

2014-01-01

Highlights: • AdSC transplantation exhibits inhibitory effect on tumor progressions of PCa cells. • AdSC-induced PCa cell apoptosis may occur via the TGF-β signaling pathway. • High expression of the TGF-β1 gene in AdSCs. - Abstract: Mesenchymal stem cells (MSCs) have generated a great deal of interest in the field of regenerative medicine. Adipose-derived stromal cells (AdSCs) are known to exhibit extensive proliferation potential and can undergo multilineage differentiation, sharing similar characteristics to bone marrow-derived MSCs. However, as the effect of AdSCs on tumor growth has not been studied sufficiently, we assessed the degree to which AdSCs affect the proliferation of prostate cancer (PCa) cell. Human AdSCs exerted an inhibitory effect on the proliferation of androgen-responsive (LNCaP) and androgen-nonresponsive (PC3) human PCa cells, while normal human dermal fibroblasts (NHDFs) did not, and in fact promoted PCa cell proliferation to a degree. Moreover, AdSCs induced apoptosis of LNCaP cells and PC3 cells, activating the caspase3/7 signaling pathway. cDNA microarray analysis suggested that AdSC-induced apoptosis in both LNCaP and PC3 cells was related to the TGF-β signaling pathway. Consistent with our in vitro observations, local transplantation of AdSCs delayed the growth of tumors derived from both LNCaP- and PC3-xenografts in immunodeficient mice. This is the first preclinical study to have directly demonstrated that AdSC-induced PCa cell apoptosis may occur via the TGF-β signaling pathway, irrespective of androgen-responsiveness. Since autologous AdSCs can be easily isolated from adipose tissue without any ethical concerns, we suggest that therapy with these cells could be a novel approach for patients with PCa

Chromosome condensation and radiation-induced G2 arrest studied by the induction of premature chromosome condensation following cell fusion

International Nuclear Information System (INIS)

Mitchell, J.B.; Bedford, J.S.

1978-01-01

When mitotic and interphase cells are fused together, the chromosomes of the interphase cell sometimes condense prematurely. The phenomenon of premature chromosome condensation (PCC) was utilized in investigating the problem of whether the chromosomes of cells suffering a radiation-induced G 2 delay are capable of condensation. Colcemide-arrested mitotic cells were fused with synchronized G 2 cells, and with irradiated cells suffering a G 2 delay. The frequency of PCC in mitotic X G 2 binucleate cells was determined. This was compared to the PCC frequency in an unirradiated synchronized population rich in G 2 cells after fusion with mitotic cells. Flash-labelling with 3 HTdR and autoradiography allowed S-phase cells to be eliminated. The frequency of G 2 PCCs was not significantly different for the irradiated G 2 -delayed or unirradiated cells. From these results it was concluded that the chromosomes of cells suffering a G 2 arrest are capable of condensation, although the involvement of the condensation process in radiation-induced G 2 delay could not be ruled out. (author)

X-irradiation-induced nuclear lesions in cultured mammaliam cells: an ultrastructural analysis

International Nuclear Information System (INIS)

Barham, S.S.; Walters, R.A.

1978-01-01

Electron-dense chromatin aggregates, hereafter referred to as lesions, have been characterized morphologically within interphase nuclei of Chinese hamster cells (line CHO) after a single acute exposure to 400, 800, 1200, or 2000 rad of x irradiation. At all doses studied, lesions were observed only after termination of radiation-induced division delay. Cell profiles were scored by electron microscopy for the presence or absence of nuclear lesions at various times after irradiation. The mitotic fraction from each irradiated population was also scored for each sample by light and electron microscopy. From these data and from simultaneous cell-density counts for each sample, it is apparent that postirradiation cell division is a prerequisite to formation of interphase nuclear lesions. Irradiated cell populations blocked in mitosis by Colcemid beyond the normal period of postirradiation division-delay failed to display nuclear lesions until after Colcemid was removed and cell division was completed. Enzyme digestions of isolated nuclei from irradiated cells with DNase I, RNase A, and Pronase suggest that the nuclear lesions are comprised primarily of chromatin. Nucleolar lesions, as well as various aberrant morphological forms of nucleoli, were also observed in cell populations after the onset of postirradiation cell division during the first 72 hr following exposure to irradiation. Delayed radiation-induced ultrastructural alterations of the nucleus included the formation of cytoplasmic invaginations into the nuclear space and inclusions of membranes within nuclei

Modeling Directional Selectivity Using Self-Organizing Delay-Aadaptation Maps

OpenAIRE

Tversky, Mr. Tal; Miikkulainen, Dr. Risto

2002-01-01

Using a delay adaptation learning rule, we model the activity-dependent development of directionally selective cells in the primary visual cortex. Based on input stimuli, a learning rule shifts delays to create synchronous arrival of spikes at cortical cells. As a result, delays become tuned creating a smooth cortical map of direction selectivity. This result demonstrates how delay adaption can serve as a powerful abstraction for modeling temporal learning in the brain.

An immunosurveillance mechanism controls cancer cell ploidy.

Science.gov (United States)

Senovilla, Laura; Vitale, Ilio; Martins, Isabelle; Tailler, Maximilien; Pailleret, Claire; Michaud, Mickaël; Galluzzi, Lorenzo; Adjemian, Sandy; Kepp, Oliver; Niso-Santano, Mireia; Shen, Shensi; Mariño, Guillermo; Criollo, Alfredo; Boilève, Alice; Job, Bastien; Ladoire, Sylvain; Ghiringhelli, François; Sistigu, Antonella; Yamazaki, Takahiro; Rello-Varona, Santiago; Locher, Clara; Poirier-Colame, Vichnou; Talbot, Monique; Valent, Alexander; Berardinelli, Francesco; Antoccia, Antonio; Ciccosanti, Fabiola; Fimia, Gian Maria; Piacentini, Mauro; Fueyo, Antonio; Messina, Nicole L; Li, Ming; Chan, Christopher J; Sigl, Verena; Pourcher, Guillaume; Ruckenstuhl, Christoph; Carmona-Gutierrez, Didac; Lazar, Vladimir; Penninger, Josef M; Madeo, Frank; López-Otín, Carlos; Smyth, Mark J; Zitvogel, Laurence; Castedo, Maria; Kroemer, Guido

2012-09-28

Cancer cells accommodate multiple genetic and epigenetic alterations that initially activate intrinsic (cell-autonomous) and extrinsic (immune-mediated) oncosuppressive mechanisms. Only once these barriers to oncogenesis have been overcome can malignant growth proceed unrestrained. Tetraploidization can contribute to oncogenesis because hyperploid cells are genomically unstable. We report that hyperploid cancer cells become immunogenic because of a constitutive endoplasmic reticulum stress response resulting in the aberrant cell surface exposure of calreticulin. Hyperploid, calreticulin-exposing cancer cells readily proliferated in immunodeficient mice and conserved their increased DNA content. In contrast, hyperploid cells injected into immunocompetent mice generated tumors only after a delay, and such tumors exhibited reduced DNA content, endoplasmic reticulum stress, and calreticulin exposure. Our results unveil an immunosurveillance system that imposes immunoselection against hyperploidy in carcinogen- and oncogene-induced cancers.

Impact of cycling cells and cell cycle regulation on Hydra regeneration.

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Buzgariu, Wanda; Wenger, Yvan; Tcaciuc, Nina; Catunda-Lemos, Ana-Paula; Galliot, Brigitte

2018-01-15

Hydra tissues are made from three distinct populations of stem cells that continuously cycle and pause in G2 instead of G1. To characterize the role of cell proliferation after mid-gastric bisection, we have (i) used flow cytometry and classical markers to monitor cell cycle modulations, (ii) quantified the transcriptomic regulations of 202 genes associated with cell proliferation during head and foot regeneration, and (iii) compared the impact of anti-proliferative treatments on regeneration efficiency. We confirm two previously reported events: an early mitotic wave in head-regenerating tips, when few cell cycle genes are up-regulated, and an early-late wave of proliferation on the second day, preceded by the up-regulation of 17 cell cycle genes. These regulations appear more intense after mid-gastric bisection than after decapitation, suggesting a position-dependent regulation of cell proliferation during head regeneration. Hydroxyurea, which blocks S-phase progression, delays head regeneration when applied before but not after bisection. This result is consistent with the fact that the Hydra central region is enriched in G2-paused adult stem cells, poised to divide upon injury, thus forming a necessary constitutive pro-blastema. However a prolonged exposure to hydroxyurea does not block regeneration as cells can differentiate apical structures without traversing S-phase, and also escape in few days the hydroxyurea-induced S-phase blockade. Thus Hydra head regeneration, which is a fast event, is highly plastic, relying on large stocks of adult stem cells paused in G2 at amputation time, which immediately divide to proliferate and/or differentiate apical structures even when S-phase is blocked. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Heterogenic final cell cycle by chicken retinal Lim1 horizontal progenitor cells leads to heteroploid cells with a remaining replicated genome.

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Shahrzad Shirazi Fard

Full Text Available Retinal progenitor cells undergo apical mitoses during the process of interkinetic nuclear migration and newly generated post-mitotic neurons migrate to their prospective retinal layer. Whereas this is valid for most types of retinal neurons, chicken horizontal cells are generated by delayed non-apical mitoses from dedicated progenitors. The regulation of such final cell cycle is not well understood and we have studied how Lim1 expressing horizontal progenitor cells (HPCs exit the cell cycle. We have used markers for S- and G2/M-phase in combination with markers for cell cycle regulators Rb1, cyclin B1, cdc25C and p27Kip1 to characterise the final cell cycle of HPCs. The results show that Lim1+ HPCs are heterogenic with regards to when and during what phase they leave the final cell cycle. Not all horizontal cells were generated by a non-apical (basal mitosis; instead, the HPCs exhibited three different behaviours during the final cell cycle. Thirty-five percent of the Lim1+ horizontal cells was estimated to be generated by non-apical mitoses. The other horizontal cells were either generated by an interkinetic nuclear migration with an apical mitosis or by a cell cycle with an S-phase that was not followed by any mitosis. Such cells remain with replicated DNA and may be regarded as somatic heteroploids. The observed heterogeneity of the final cell cycle was also seen in the expression of Rb1, cyclin B1, cdc25C and p27Kip1. Phosphorylated Rb1-Ser608 was restricted to the Lim1+ cells that entered S-phase while cyclin B1 and cdc25C were exclusively expressed in HPCs having a basal mitosis. Only HPCs that leave the cell cycle after an apical mitosis expressed p27Kip1. We speculate that the cell cycle heterogeneity with formation of heteroploid cells may present a cellular context that contributes to the suggested propensity of these cells to generate cancer when the retinoblastoma gene is mutated.

Cytotoxic effects of ultra-diluted remedies on breast cancer cells.

Science.gov (United States)

Frenkel, Moshe; Mishra, Bal Mukund; Sen, Subrata; Yang, Peiying; Pawlus, Alison; Vence, Luis; Leblanc, Aimee; Cohen, Lorenzo; Banerji, Pratip; Banerji, Prasanta

2010-02-01

The use of ultra-diluted natural products in the management of disease and treatment of cancer has generated a lot of interest and controversy. We conducted an in vitro study to determine if products prescribed by a clinic in India have any effect on breast cancer cell lines. We studied four ultra-diluted remedies (Carcinosin, Phytolacca, Conium and Thuja) against two human breast adenocarcinoma cell lines (MCF-7 and MDA-MB-231) and a cell line derived from immortalized normal human mammary epithelial cells (HMLE). The remedies exerted preferential cytotoxic effects against the two breast cancer cell lines, causing cell cycle delay/arrest and apoptosis. These effects were accompanied by altered expression of the cell cycle regulatory proteins, including downregulation of phosphorylated Rb and upregulation of the CDK inhibitor p27, which were likely responsible for the cell cycle delay/arrest as well as induction of the apoptotic cascade that manifested in the activation of caspase 7 and cleavage of PARP in the treated cells. The findings demonstrate biological activity of these natural products when presented at ultra-diluted doses. Further in-depth studies with additional cell lines and animal models are warranted to explore the clinical applicability of these agents.

Novel Coiled-Coil Cell Division Factor ZapB Stimulates Z Ring Assembly and Cell Division

DEFF Research Database (Denmark)

Ebersbach, Gitte; Galli, Elizabeth; Møller-Jensen, Jakob

2008-01-01

Formation of the Z ring is the first known event in bacterial cell division. However, it is not yet known how the assembly and contraction of the Z ring is regulated. Here, we identify a novel cell division factor ZapB in Escherichia coli that simultaneously stimulates Z ring assembly and cell...... division. Deletion of zapB resulted in delayed cell division and the formation of ectopic Z rings and spirals whereas overexpression of ZapB resulted in nucleoid condensation and aberrant cell divisions. Localization of ZapB to the divisome depended on FtsZ but not FtsA, ZipA or FtsI and ZapB interacted...... with FtsZ in a bacterial two-hybrid analysis. The simultaneous inactivation of FtsA and ZipA prevented Z ring assembly and ZapB localization. Time lapse microscopy showed that ZapB-GFP is present at mid-cell in a pattern very similar to that of FtsZ. Cells carrying a zapB deletion and the ftsZ84ts allele...

Dose-rate effects in synchronous mammalian cells in culture. II. A comparison of the life cycle of HeLa cells during continuous irradiation or multiple-dose fractionation

International Nuclear Information System (INIS)

Mitchell, J.B.; Bedford, J.S.

1977-01-01

The life cycle of synchronized S3 HeLa cells was examined during continuous irradiation at a dose rate of approximately 37 rad/hr and during multiple dose fractionation schedules of the same average dose rate (total dose / overall time = average dose rate). For all regimes given at this dose rate the effects on the life cyclee were similar. Cells progressed through G1 and S without appreciable delay and experienced a minimum G2 delay of about 10 hr. Cells eventually entered mitosis but virtually none were able to complete a successful division

The Wound Microenvironment Reprograms Schwann Cells to Invasive Mesenchymal-like Cells to Drive Peripheral Nerve Regeneration.

Science.gov (United States)

Clements, Melanie P; Byrne, Elizabeth; Camarillo Guerrero, Luis F; Cattin, Anne-Laure; Zakka, Leila; Ashraf, Azhaar; Burden, Jemima J; Khadayate, Sanjay; Lloyd, Alison C; Marguerat, Samuel; Parrinello, Simona

2017-09-27

Schwann cell dedifferentiation from a myelinating to a progenitor-like cell underlies the remarkable ability of peripheral nerves to regenerate following injury. However, the molecular identity of the differentiated and dedifferentiated states in vivo has been elusive. Here, we profiled Schwann cells acutely purified from intact nerves and from the wound and distal regions of severed nerves. Our analysis reveals novel facets of the dedifferentiation response, including acquisition of mesenchymal traits and a Myc module. Furthermore, wound and distal dedifferentiated Schwann cells constitute different populations, with wound cells displaying increased mesenchymal character induced by localized TGFβ signaling. TGFβ promotes invasion and crosstalks with Eph signaling via N-cadherin to drive collective migration of the Schwann cells across the wound. Consistently, Tgfbr2 deletion in Schwann cells resulted in misdirected and delayed reinnervation. Thus, the wound microenvironment is a key determinant of Schwann cell identity, and it promotes nerve repair through integration of multiple concerted signals. VIDEO ABSTRACT. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

The effect of caffeine on radiation-induced division delay

International Nuclear Information System (INIS)

Snyder, M.H.; Kimler, B.F.; Leeper, D.B.

1977-01-01

Caffeine (100 μg/ml) was added to monolayer cultures of Chinese hamster ovary cells coincident with 60 Co γ-irradiation (75 to 300 rad). The results indicated that caffeine (at concentrations that did not perturb cell-cycle progression as monitored by the mitotic selection technique) exerted a protective effect against radiation-induced division delay. This protection consisted of an increase in the number of cells that were refractory to the radiation insult, as well as a decrease in the average time that non-refractory cells were delayed before they recovered their ability to progress through the cell cycle. (U.K.)

Effect of caffeine on radiation-induced mitotic delay: delayed expression of G2 arrest

International Nuclear Information System (INIS)

Rowley, R.; Zorch, M.; Leeper, D.B.

1984-01-01

In the presence of 5 mM caffeine, irradiated (1.5 Gy) S and G 2 cells progressed to mitosis in register and without arrest in G 2 . Caffeine (5 mM) markedly reduced mitotic delay even after radiation doses up to 20 Gy. When caffeine was removed from irradiated (1.5 Gy) and caffeine-treated cells, a period of G 2 arrest followed, similar in length to that produced by radiation alone. The arrest expressed was independent of the duration of the caffeine treatment for exposures up to 3 hr. The similarity of the response to the cited effects of caffeine on S-phase delay suggests a common basis for delay induction in S and G 2 phases

Coordination between chromosome replication, segregation, and cell division in Caulobacter crescentus

DEFF Research Database (Denmark)

Jensen, Rasmus Bugge

2006-01-01

Progression through the Caulobacter crescentus cell cycle is coupled to a cellular differentiation program. The swarmer cell is replicationally quiescent, and DNA replication initiates at the swarmer-to-stalked cell transition. There is a very short delay between initiation of DNA replication...

Msx2 alters the timing of retinal ganglion cells fate commitment and differentiation

Energy Technology Data Exchange (ETDEWEB)

Jiang, Shao-Yun, E-mail: jiangshaoyun@yahoo.com [School of Dentistry, Tianjin Medical University, 12 Qi Xiang Tai Street, Tianjin 300070 (China); Wang, Jian-Tao, E-mail: wangjiantao65@hotmail.com [Eye Center, Tianjin Medical University, 64 Tongan Road, Tianjin 300070 (China); Dohney Eye Institute, Keck School of Medicine, University of Southern California, 1355 San Pablo Street, DOH 314, Los Angeles, CA 90033 (United States)

2010-05-14

Timing of cell fate commitment determines distinct retinal cell types, which is believed to be controlled by a tightly coordinated regulatory program of proliferation, cell cycle exit and differentiation. Although homeobox protein Msx2 could induce apoptosis of optic vesicle, it is unclear whether Msx2 regulates differentiation and cell fate commitment of retinal progenitor cells (RPCs) to retinal ganglion cells (RGCs). In this study, we show that overexpression of Msx2 transiently suppressed the expression of Cyclin D1 and blocked cell proliferation. Meanwhile, overexpression of Msx2 delayed the expression of RGC-specific differentiation markers (Math5 and Brn3b), which showed that Msx2 could affect the timing of RGCs fate commitment and differentiation by delaying the timing of cell cycle exit of retinal progenitors. These results indicate Msx2 possesses dual regulatory functions in controlling cell cycle progression of retinal RPCs and timing of RGCs differentiation.

Fate of tumor cells injected into left ventricle of heart in BALB/c mice: role of natural killer cells

DEFF Research Database (Denmark)

Basse, P; Hokland, P; Heron, I

1988-01-01

The arrest, retention, and elimination (i.e., clearance) of radiolabeled YAC-1 lymphoma cells injected either iv or into the left ventricle (LV) of the heart were studied in male BALB/c mice, with special emphasis on the role of natural killer (NK) cells. After iv injection YAC-1 cells were...... extent, the bone, skin, and muscle. The only organs that could arrest the LV-injected tumor cells were the lungs and the liver. In the lungs clearance of YAC-1 cells began immediately after the cells were arrested. However, the rate of clearance could be almost abrogated by pretreatment of the recipients...... with anti-asialo GM1 antiserum, which destroys most of the NK cells in vivo and strongly depresses the in vitro NK cell activity. In contrast, YAC-1 cells arrested in the liver were not cleared from this organ during the first 1-2 hours after arrest. After this delay clearance of the cells commenced...

Cell transplantation for Parkinson's disease

Institute of Scientific and Technical Information of China (English)

Jia Liu; Hongyun Huang

2006-01-01

OBJECTIVE: The motor symptoms of Parkinson's disease (PD) can be improved by cell transplantation,which has caught general attention from the field of the therapy for PD recently. In this paper, we summarize the cell-based therapy for PD.DATA SOURCES: A search for English literature related to the cellular transplantation of PD from January 1979to July 2006 was conducted in Medline with the key words of "Parkinson's disease, cell transplantation,embryonic stem cells, neural stem cells".STUDY SELECTTON: Data were checked in the first trial, and literatures about PD and cell transplantation were selected. Inclusive criteria: ① PD; ② Cell transplantation. Exclusive criteria: repetitive researches.DATA EXTRACTTON: A total of 100 papers related to cellular transplant and PD were collected and 41literatures were in accordance with the inclusive criteria.DATA SYNTHESIS: PD is a neural degeneration disease that threatens the health of the aged people, and most traditional therapeusis cannot delay its pathological proceeding. Cell transplantation is becoming popular as a new therapeutic tool, and the cells used to transplant mainly included dopamine-secreting cells, fetal ventral mesencephalic cells, embryonic stem cells and neural stem cells up to now. Animal experiment and clinical test demonstrate that cell transplantation can relieve the motor symptoms of Parkinson's disease obviously, but there are some problems need to be solved.CONCLUSTON: Cell transplantation has visible therapeutic efficacy on PD. Following the improvement of technique, and we have enough cause to credit that cell therapy may cure PD in the future.

Human-induced pluripotent stem cell-derived cardiomyocytes from cardiac progenitor cells: effects of selective ion channel blockade.

Science.gov (United States)

Altomare, Claudia; Pianezzi, Enea; Cervio, Elisabetta; Bolis, Sara; Biemmi, Vanessa; Benzoni, Patrizia; Camici, Giovanni G; Moccetti, Tiziano; Barile, Lucio; Vassalli, Giuseppe

2016-12-01

Human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes are likely to revolutionize electrophysiological approaches to arrhythmias. Recent evidence suggests the somatic cell origin of hiPSCs may influence their differentiation potential. Owing to their cardiomyogenic potential, cardiac-stromal progenitor cells (CPCs) are an interesting cellular source for generation of hiPSC-derived cardiomyocytes. The effect of ionic current blockade in hiPSC-derived cardiomyocytes generated from CPCs has not been characterized yet. Human-induced pluripotent stem cell-derived cardiomyocytes were generated from adult CPCs and skin fibroblasts from the same individuals. The effect of selective ionic current blockade on spontaneously beating hiPSC-derived cardiomyocytes was assessed using multi-electrode arrays. Cardiac-stromal progenitor cells could be reprogrammed into hiPSCs, then differentiated into hiPSC-derived cardiomyocytes. Human-induced pluripotent stem cell-derived cardiomyocytes of cardiac origin showed higher upregulation of cardiac-specific genes compared with those of fibroblastic origin. Human-induced pluripotent stem cell-derived cardiomyocytes of both somatic cell origins exhibited sensitivity to tetrodotoxin, a blocker of Na +  current (I Na ), nifedipine, a blocker of L-type Ca 2+  current (I CaL ), and E4031, a blocker of the rapid component of delayed rectifier K +  current (I Kr ). Human-induced pluripotent stem cell-derived cardiomyocytes of cardiac origin exhibited sensitivity to JNJ303, a blocker of the slow component of delayed rectifier K +  current (I Ks ). In hiPSC-derived cardiomyocytes of cardiac origin, I Na , I CaL , I Kr , and I Ks were present as tetrodotoxin-, nifedipine-, E4031-, and JNJ303-sensitive currents, respectively. Although cardiac differentiation efficiency was improved in hiPSCs of cardiac vs. non-cardiac origin, no major functional differences were observed between hiPSC-derived cardiomyocytes of different somatic

Mucosal B Cells Are Associated with Delayed SIV Acquisition in Vaccinated Female but Not Male Rhesus Macaques Following SIVmac251 Rectal Challenge.

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Iskra Tuero

2015-08-01

Full Text Available Many viral infections, including HIV, exhibit sex-based pathogenic differences. However, few studies have examined vaccine-related sex differences. We compared immunogenicity and protective efficacy of monomeric SIV gp120 with oligomeric SIV gp140 in a pre-clinical rhesus macaque study and explored a subsequent sex bias in vaccine outcome. Each immunization group (16 females, 8 males was primed twice mucosally with replication-competent Ad-recombinants encoding SIVsmH4env/rev, SIV239gag and SIV239nefΔ1-13 and boosted twice intramuscularly with SIVmac239 monomeric gp120 or oligomeric gp140 in MF59 adjuvant. Controls (7 females, 5 males received empty Ad and MF59. Up to 9 weekly intrarectal challenges with low-dose SIVmac251 were administered until macaques became infected. We assessed vaccine-induced binding, neutralizing, and non-neutralizing antibodies, Env-specific memory B cells and plasmablasts/plasma cells (PB/PC in bone marrow and rectal tissue, mucosal Env-specific antibodies, and Env-specific T-cells. Post-challenge, only one macaque (gp140-immunized remained uninfected. However, SIV acquisition was significantly delayed in vaccinated females but not males, correlated with Env-specific IgA in rectal secretions, rectal Env-specific memory B cells, and PC in rectal tissue. These results extend previous correlations of mucosal antibodies and memory B cells with protective efficacy. The gp140 regimen was more immunogenic, stimulating elevated gp140 and cyclic V2 binding antibodies, ADCC and ADCP activities, bone marrow Env-specific PB/PC, and rectal gp140-specific IgG. However, immunization with gp120, the form of envelope immunogen used in RV144, the only vaccine trial to show some efficacy, provided more significant acquisition delay. Further over 40 weeks of follow-up, no gp120 immunized macaques met euthanasia criteria in contrast to 7 gp140-immunized and 2 control animals. Although males had higher binding antibodies than females, ADCC

Mucosal B Cells Are Associated with Delayed SIV Acquisition in Vaccinated Female but Not Male Rhesus Macaques Following SIVmac251 Rectal Challenge.

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Tuero, Iskra; Mohanram, Venkatramanan; Musich, Thomas; Miller, Leia; Vargas-Inchaustegui, Diego A; Demberg, Thorsten; Venzon, David; Kalisz, Irene; Kalyanaraman, V S; Pal, Ranajit; Ferrari, Maria Grazia; LaBranche, Celia; Montefiori, David C; Rao, Mangala; Vaccari, Monica; Franchini, Genoveffa; Barnett, Susan W; Robert-Guroff, Marjorie

2015-08-01

Many viral infections, including HIV, exhibit sex-based pathogenic differences. However, few studies have examined vaccine-related sex differences. We compared immunogenicity and protective efficacy of monomeric SIV gp120 with oligomeric SIV gp140 in a pre-clinical rhesus macaque study and explored a subsequent sex bias in vaccine outcome. Each immunization group (16 females, 8 males) was primed twice mucosally with replication-competent Ad-recombinants encoding SIVsmH4env/rev, SIV239gag and SIV239nefΔ1-13 and boosted twice intramuscularly with SIVmac239 monomeric gp120 or oligomeric gp140 in MF59 adjuvant. Controls (7 females, 5 males) received empty Ad and MF59. Up to 9 weekly intrarectal challenges with low-dose SIVmac251 were administered until macaques became infected. We assessed vaccine-induced binding, neutralizing, and non-neutralizing antibodies, Env-specific memory B cells and plasmablasts/plasma cells (PB/PC) in bone marrow and rectal tissue, mucosal Env-specific antibodies, and Env-specific T-cells. Post-challenge, only one macaque (gp140-immunized) remained uninfected. However, SIV acquisition was significantly delayed in vaccinated females but not males, correlated with Env-specific IgA in rectal secretions, rectal Env-specific memory B cells, and PC in rectal tissue. These results extend previous correlations of mucosal antibodies and memory B cells with protective efficacy. The gp140 regimen was more immunogenic, stimulating elevated gp140 and cyclic V2 binding antibodies, ADCC and ADCP activities, bone marrow Env-specific PB/PC, and rectal gp140-specific IgG. However, immunization with gp120, the form of envelope immunogen used in RV144, the only vaccine trial to show some efficacy, provided more significant acquisition delay. Further over 40 weeks of follow-up, no gp120 immunized macaques met euthanasia criteria in contrast to 7 gp140-immunized and 2 control animals. Although males had higher binding antibodies than females, ADCC and ADCP

Differential radiosensitivity among B cell subpopulations

International Nuclear Information System (INIS)

Riggs, J.E.

1988-01-01

The selective radiosensitivity of sIgM >> sIgD marginal zone B cells is associated with the selective loss of B cell function. The simultaneous restoration of impaired function and recovery of these cells with time supports this premise. B cell recovery, delayed one week after irradiation, is in progress at two weeks, and virtually complete by three weeks. XID mice reveal similar recovery kinetics although there are fewer recovering cells and these bear reduced levels of Ia. This observation represents additional evidence that xid B cells are distinct from those of normal mice. The simultaneous loss, and concurrent recovery, of sIgM >> sIgD B cells and TI-2 responsiveness in irradiated mice suggests the existence of a unique B cell subpopulation possessing both phenotypes. Additional support for this hypothesis is provided by demonstrating that splenocytes, depleted of IgD + cells adoptively reconstitute this response in XID mice. The peritoneal B cell pool, which, compared to the spleen, consist of increased numbers of sIgM >> sIgD B cells, is shown to be a source of radiosensitive B cells that are TI-2 responsive. These observations represent additional evidence for an association between sIgM >> sIgD B cells and TI-2 responsiveness

[Ischemic Changes in the Electrocardiogram and Circulatory Collapse Accompanied by Severe Anemia Owing to the Delay of Red Blood Cell Concentrate Transfusion in Two Patients with Intraoperative Massive Bleeding].

Science.gov (United States)

Horiuchi, Toshinori; Noguchi, Teruo; Kurita, Naoko; Yamaguchi, Ayako; Takeda, Masafumi; Sha, Keiichi; Nagahata, Toshihiro

2016-01-01

We present two patients developing intraoperative massive bleeding and showed ischemic changes in the electrocardiogram and circulatory collapse accompanied by severe anemia owing to the delay of red blood cell concentrate transfusion. One patient underwent hepatectomy and the other pancreaticoduodenectomy. Their lowest hemoglobin concentration was around 2 g x dl(-1), and they showed ischemic changes in the electrocardiogram and severe decreases in blood pressure. The former received compatible red blood cell concentrate and the latter received uncrossmatched same blood group red blood cell concentrate immediately, and their electrocardiogram and blood pressure quickly improved. To avoid life-threatening anemia, emergency red blood cell concentrate transfusion including compatible different blood group transfusion should be applied for intraoperative massive bleeding.

Hopf bifurcation of a free boundary problem modeling tumor growth with two time delays

International Nuclear Information System (INIS)

Xu Shihe

2009-01-01

In this paper, a free boundary problem modeling tumor growth with two discrete delays is studied. The delays respectively represents the time taken for cells to undergo mitosis and the time taken for the cell to modify the rate of cell loss due to apoptosis. We show the influence of time delays on the Hopf bifurcation when one of delays as a bifurcation parameter.

Changes from 1992 to 2002 in the pretreatment delay for patients with squamous cell carcinoma of larynx or pharynx: a Danish nationwide survey from DAHANCA

DEFF Research Database (Denmark)

Primdahl, Hanne; Nielsen, Anni Linnet; Larsen, Susanne

2006-01-01

In Denmark, a general impression of prolonged pretreatment delay for patients with head and neck cancer led to a nationwide study of time spans from symptom debut over first health care contact to start of treatment. Charts of consecutive new patients with squamous cell carcinoma of the pharynx a...

A Simple Mathematical Model Inspired by the Purkinje Cells: From Delayed Travelling Waves to Fractional Diffusion.

Science.gov (United States)

Dipierro, Serena; Valdinoci, Enrico

2018-07-01

Recently, several experiments have demonstrated the existence of fractional diffusion in the neuronal transmission occurring in the Purkinje cells, whose malfunctioning is known to be related to the lack of voluntary coordination and the appearance of tremors. Also, a classical mathematical feature is that (fractional) parabolic equations possess smoothing effects, in contrast with the case of hyperbolic equations, which typically exhibit shocks and discontinuities. In this paper, we show how a simple toy-model of a highly ramified structure, somehow inspired by that of the Purkinje cells, may produce a fractional diffusion via the superposition of travelling waves that solve a hyperbolic equation. This could suggest that the high ramification of the Purkinje cells might have provided an evolutionary advantage of "smoothing" the transmission of signals and avoiding shock propagations (at the price of slowing a bit such transmission). Although an experimental confirmation of the possibility of such evolutionary advantage goes well beyond the goals of this paper, we think that it is intriguing, as a mathematical counterpart, to consider the time fractional diffusion as arising from the superposition of delayed travelling waves in highly ramified transmission media. The case of a travelling concave parabola with sufficiently small curvature is explicitly computed. The new link that we propose between time fractional diffusion and hyperbolic equation also provides a novelty with respect to the usual paradigm relating time fractional diffusion with parabolic equations in the limit. This paper is written in such a way as to be of interest to both biologists and mathematician alike. In order to accomplish this aim, both complete explanations of the objects considered and detailed lists of references are provided.

Changes in distribution of cell cycle phases and DNA content in HeLa S3 cell after irradiation

International Nuclear Information System (INIS)

Wang Shunbao

1992-01-01

The effects of irradiation and hyperthermia on the distribution in various phases and DNA content of HeLa S 3 cells were analyzed by flow cytometry and an image analysis instrument. A marked increase in DNA content from 6.718 to 9.614(AU) in HeLa S 3 cells after 6 Gy irradiation was seen to correspond with the changes in the distribution of various phases in G 2 + M, from 22% to 52%. Meanwhile, the surviving fraction of HeLa S 3 cells after 6 Gy irradiation was less than 1%. However, after heating at 44 deg C for 10 min, the amount of cells in G 2 + M increased from 22.5% to 52.5% and the surviving fraction after hyperthermia was less than 2.65%. The changes in distribution of various phases after Ir-192 irradiation were similar to those seen after X-ray irradiation. The delay of G 2 + M phase after treatment with 8 Gy plus heating at 44 deg C for 7 min in HeLa S 3 cells was similar to that seen in the case of treatment with 8 Gy alone. As the surviving fraction accompanying the G 2 + M delay after irradiation plus heat treatment was very low, we suggest that the changes of distribution in various phases of HeLa S 3 cells after treatment might be used as a rapid indicator of serious injury

Effects of blood transportation on human peripheral mononuclear cell yield, phenotype and function: implications for immune cell biobanking.

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Anita Posevitz-Fejfár

Full Text Available Human biospecimen collection, processing and preservation are rapidly emerging subjects providing essential support to clinical as well as basic researchers. Unlike collection of other biospecimens (e.g. DNA and serum, biobanking of viable immune cells, such as peripheral blood mononuclear cells (PBMC and/or isolated immune cell subsets is still in its infancy. While certain aspects of processing and freezing conditions have been studied in the past years, little is known about the effect of blood transportation on immune cell survival, phenotype and specific functions. However, especially for multicentric and cooperative projects it is vital to precisely know those effects. In this study we investigated the effect of blood shipping and pre-processing delay on immune cell phenotype and function both on cellular and subcellular levels. Peripheral blood was collected from healthy volunteers (n = 9: at a distal location (shipped overnight and in the central laboratory (processed immediately. PBMC were processed in the central laboratory and analyzed post-cryopreservation. We analyzed yield, major immune subset distribution, proliferative capacity of T cells, cytokine pattern and T-cell receptor signal transduction. Results show that overnight transportation of blood samples does not globally compromise T- cell subsets as they largely retain their phenotype and proliferative capacity. However, NK and B cell frequencies, the production of certain PBMC-derived cytokines and IL-6 mediated cytokine signaling pathway are altered due to transportation. Various control experiments have been carried out to compare issues related to shipping versus pre-processing delay on site. Our results suggest the implementation of appropriate controls when using multicenter logistics for blood transportation aiming at subsequent isolation of viable immune cells, e.g. in multicenter clinical trials or studies analyzing immune cells/subsets. One important conclusion might

GM-CSF produced by non-hematopoietic cells is required for early epithelial cell proliferation and repair of injured colonic mucosa1,2

Science.gov (United States)

Egea, Laia; McAllister, Christopher S.; Lakhdari, Omar; Minev, Ivelina; Shenouda, Steve; Kagnoff, Martin F.

2012-01-01

GM-CSF is a growth factor that promotes the survival and activation of macrophages and granulocytes, and dendritic cell (DC) differentiation and survival in vitro. The mechanism by which exogenous GM-CSF ameliorates the severity of Crohn’s disease in humans and colitis in murine models has been considered mainly to reflect its activity on myeloid cells. We used GM-CSF deficient (GM-CSF−/−) mice to probe the functional role of endogenous host-produced GM-CSF in a colitis model induced after injury to the colon epithelium. Dextran sodium sulfate (DSS) at doses that resulted in little epithelial damage and mucosal ulceration in wild type (WT) mice resulted in marked colon ulceration and delayed ulcer healing in GM-CSF−/− mice. Colon crypt epithelial cell proliferation in vivo was significantly decreased in GM-CSF−/− mice at early times after DSS injury. This was paralleled by decreased expression of crypt epithelial cell genes involved in cell cycle, proliferation, and wound healing. Decreased crypt cell proliferation and delayed ulcer healing in GM-CSF−/− mice were rescued by exogenous GM-CSF, indicating the lack of a developmental abnormality in the epithelial cell proliferative response in those mice. Non-hematopoietic cells and not myeloid cells produced the GM-CSF important for colon epithelial proliferation after DSS-induced injury as revealed by bone marrow chimera and DC depletion experiments, with colon epithelial cells being the cellular source of GM-CSF. Endogenous epithelial cell produced GM-CSF has a novel non-redundant role in facilitating epithelial cell proliferation and ulcer healing in response to injury of the colon crypt epithelium. PMID:23325885

Ovarian Stem Cell Nests in Reproduction and Ovarian Aging.

Science.gov (United States)

Ye, Haifeng; Zheng, Tuochen; Li, Wei; Li, Xiaoyan; Fu, Xinxin; Huang, Yaoqi; Hu, Chuan; Li, Jia; Huang, Jian; Liu, Zhengyv; Zheng, Liping; Zheng, Yuehui

2017-01-01

The fixed primordial follicles pool theory, which monopolized reproductive medicine for more than one hundred years, has been broken by the discovery, successful isolation and establishment of ovarian stem cells. It has brought more hope than ever of increasing the size of primordial follicle pool, improving ovarian function and delaying ovarian consenescence. Traditional view holds that stem cell aging contributes to the senility of body and organs. However, in the process of ovarian aging, the main factor leading to the decline of the reproductive function is the aging and degradation of ovarian stem cell nests, rather than the senescence of ovarian germ cells themselves. Recent studies have found that the immune system and circulatory system are involved in the formation of ovarian germline stem cell niches, as well as regulating the proliferation and differentiation of ovarian germline stem cells through cellular and hormonal signals. Therefore, we can improve ovarian function and delay ovarian aging by improving the immune system and circulatory system, which will provide an updated program for the treatment of premature ovarian failure (POF) and infertility. © 2017 The Author(s). Published by S. Karger AG, Basel.

A Model of Dendritic Cell Therapy for Melanoma

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Ami eRadunskaya

2013-03-01

Full Text Available Dendritic cells are a promising immunotherapy tool for boosting an individual's antigen specific immune response to cancer. We develop a mathematical model using differential and delay-differential equations to describe the interactions between dendritic cells, effector-immune cells and tumor cells. We account for the trafficking of immune cells between lymph, blood, and tumor compartments. Our model reflects experimental results both for dendritic-cell trafficking and for immune suppression of tumor growth in mice. In addition, in silico experiments suggest more effective immunotherapy treatment protocols can be achieved by modifying dose location and schedule. A sensitivity analysis of the model reveals which patient-specific parameters have the greatest impact on treatment efficacy.

Rituximab enhances radiation-triggered apoptosis in non-Hodgkin's lymphoma cells via caspase-dependent and - independent mechanisms

International Nuclear Information System (INIS)

Skvortsova, I.; Skvortsov, S.; Popper, B.A.; Haidenberger, A.; Saurer, M.; Gunkel, A.R.; Zwierzina, H.; Lukas, P.

2006-01-01

Rituximab (RTX), a chimeric human anti-CD20 monoclonal antibody, is currently employed in the treatment of malignant non-Hodgkin's lymphoma (NHL) either alone or in combination with other cytotoxic approaches. The present study examines the effects of ionizing radiation in combination with RTX on proliferation and apoptosis development in B-lymphoma RL and Raji cells. RTX was used at a concentration of 10 μg/mL 24 hours prior to irradiation at a single dose of 9 Gy. CD20 expression, cell viability, apoptosis, mitochondrial membrane potential and apoptosis-related proteins were evaluated in the treated B cells. The constitutive level of CD20 expression in RL and Raji lymphoma cells did not play an essential role in RTX-induced cell growth delay. Both lymphoma cells showed similar inhibition of cell proliferation without apoptosis development in response to RTX treatment. Exposure to ionizing radiation induced cell growth delay and apoptosis in RL cells, whereas Raji cells showed moderate radio-resistance and activation of cell growth at 24 hours after irradiation, which was accompanied by increased radiation-triggered CD20 expression. The simultaneous exposure of lymphoma cells to ionizing radiation and RTX abrogated radioresistance of Raji cells and significantly enhanced cell growth delay and apoptosis in RL cells. X-linked inhibitor of apoptosis protein (XIAP) and the inducible form of heat shock protein 70 (Hsp70) were positively modulated by RTX in combination with ionizing radiation in order to induce apoptosis. Furthermore, it was demonstrated that mitochondrial membrane potential dissipation is not an essential component to induce apoptosis-inducing factor (AIF) maturation and apoptosis. Our results show that RTX-triggered enhancement of radiation-induced apoptosis and cell growth delay is achieved by modulation of proteins involved in programmed cell death. (author)

Natural killer cells promote early CD8 T cell responses against cytomegalovirus.

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Scott H Robbins

2007-08-01

Full Text Available Understanding the mechanisms that help promote protective immune responses to pathogens is a major challenge in biomedical research and an important goal for the design of innovative therapeutic or vaccination strategies. While natural killer (NK cells can directly contribute to the control of viral replication, whether, and how, they may help orchestrate global antiviral defense is largely unknown. To address this question, we took advantage of the well-defined molecular interactions involved in the recognition of mouse cytomegalovirus (MCMV by NK cells. By using congenic or mutant mice and wild-type versus genetically engineered viruses, we examined the consequences on antiviral CD8 T cell responses of specific defects in the ability of the NK cells to control MCMV. This system allowed us to demonstrate, to our knowledge for the first time, that NK cells accelerate CD8 T cell responses against a viral infection in vivo. Moreover, we identify the underlying mechanism as the ability of NK cells to limit IFN-alpha/beta production to levels not immunosuppressive to the host. This is achieved through the early control of cytomegalovirus, which dramatically reduces the activation of plasmacytoid dendritic cells (pDCs for cytokine production, preserves the conventional dendritic cell (cDC compartment, and accelerates antiviral CD8 T cell responses. Conversely, exogenous IFN-alpha administration in resistant animals ablates cDCs and delays CD8 T cell activation in the face of NK cell control of viral replication. Collectively, our data demonstrate that the ability of NK cells to respond very early to cytomegalovirus infection critically contributes to balance the intensity of other innate immune responses, which dampens early immunopathology and promotes optimal initiation of antiviral CD8 T cell responses. Thus, the extent to which NK cell responses benefit the host goes beyond their direct antiviral effects and extends to the prevention of innate

Corruption of the Fas pathway delays the pulmonary clearance of murine osteosarcoma cells, enhances their metastatic potential, and reduces the effect of aerosol gemcitabine.

Science.gov (United States)

Gordon, Nancy; Koshkina, Nadezhda V; Jia, Shu-Fang; Khanna, Chand; Mendoza, Arnulfo; Worth, Laura L; Kleinerman, Eugenie S

2007-08-01

Pulmonary metastases continue to be a significant problem in osteosarcoma. Apoptosis dysfunction is known to influence tumor development. Fas (CD95, APO-1)/FasL is one of the most extensively studied apoptotic pathways. Because FasL is constitutively expressed in the lung, cells that express Fas should be eliminated by lung endothelium. Cells with low or no cell surface Fas expression may be able to evade this innate defense mechanism. The purpose of these studies was to evaluate Fas expression in osteosarcoma lung metastases and the effect of gemcitabine on Fas expression and tumor growth. Using the K7M2 murine osteosarcoma model, Fas expression was quantified using immunohistochemistry. High levels of Fas were present in primary tumors, but no Fas expression was present in actively growing lung metastases. Blocking the Fas pathway using Fas-associated death domain dominant-negative delayed tumor cell clearance from the lung and increased metastatic potential. Treatment of mice with aerosol gemcitabine resulted in increased Fas expression and subsequent tumor regression. We conclude that corruption of the Fas pathway is critical to the ability of osteosarcoma cells to grow in the lung. Agents such as gemcitabine that up-regulate cell surface Fas expression may therefore be effective in treating osteosarcoma lung metastases. These data also suggest that an additional mechanism by which gemcitabine induces regression of osteosarcoma lung metastases is mediated by enhancing the sensitivity of the tumor cells to the constitutive FasL in the lung.

Factors controlling the recirculation of haematopoietic stem cells

International Nuclear Information System (INIS)

Petrov, R.V.; Khaitov, R.M.; Alejnikova, N.V.; Gulak, L.V.

1976-01-01

Influence of thymectomy on the rate of migration and differentiation of haematopoietic stem cells from a shielded part of the bone marrow has been studied on mice X-irradiated with a lethal dose. Inhibition of the migration rate and delay in differentiation of stem cells into colonies of granuloid type have been detected in the thymectomized mice. Transplantation of syngeneic cells of the thymus or lymph nodes to thymectomized mice increases the number of colonies in the spleen and restores the routine way of differentiation of haematopoietic stem cells. It is concluded that the processes of migration and differentiation of haematopoietic stem cells are thymus-dependent

Immunogenicity of guinea pig cells transformed in culture by chemical carcinogens.

Science.gov (United States)

Ohanian, S H; McCabe, R P; Evans, C H

1981-12-01

The immunogenicity of inbred strain 2/N guinea pig fibroblasts transformed to the malignant state in vitro by chemical carcinogens was evaluated with the use of a variety of in vivo and in vitro methods including delayed-type hypersensitivity skin and tumor transplantation tests and analysis of antibody production by immunofluorescence, complement fixation, and staphylococcal protein A binding tests. Neoplastic transformation was induced by direct treatment of cells in culture with benzo[a]pyrene, 3-methylcholanthrene, or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or by the host-mediated method by which fetuses were exposed to diethylnitrosamine or MNNG in vivo prior to cell culture. Rabbits and syngeneic guinea pigs were inoculated with unirradiated and X-irradiated clonally derived cells. Delayed hypersensitivity skin reactions to immunizing or other cells were equivalent in immunized or control guinea pigs, and no protection to tumor outgrowth from a challenge inoculum of immunizing cells was observed. Antibody activity induced in the sera of immunized guinea pigs was cross-reactive and removed by absorption with nontumorigenic cells. Rabbit antisera after absorption with fetal guinea pig cells were nonreactive with the specific immunizing or other culture cells. Chemical carcinogen-induced neoplastic transformation of guinea pig cells can, therefore, occur without formation of detectable, individually distinct cell surface tumor-specific neoantigens.

Immunogenicity of guinea pig cells transformed in culture by chemical carcinogens

International Nuclear Information System (INIS)

Ohanian, S.H.; McCabe, R.P.; Evans, C.H.

1981-01-01

The immunogenicity of inbred strain 2/N guinea pig fibroblasts transformed to the malignant state in vitro by chemical carcinogens was evaluated with the use of a variety of in vivo and in vitro methods including delayed-type hypersensitivity skin and tumor transplantation tests and analysis of antibody production by immunofluorescence, complement fixation, and staphylococcal protein A binding tests. Neoplastic transformation was induced by direct treatment of cells in culture with benzo[a]pyrene, 3-methylcholanthrene, or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or by the host-mediated method by which fetuses were exposed to diethylnitrosamine or MNNG in vivo prior to cell culture. Rabbits and syngeneic guinea pigs were inoculated with unirradiated and X-irradiated clonally derived cells. Delayed hypersensitivity skin reactions to immunizing or other cells were equivalent in immunized or control guinea pigs, and no protection to tumor outgrowth from a challenge inoculum of immunizing cells was observed. Antibody activity induced in the sera of immunized guinea pigs was cross-reactive and removed by absorption with nontumorigenic cells. Rabbit anitsera after absorption with fetal guinea pig cells were nonreactive with the specific immunizing or other cultured cells. Chemical carcinogen-induced neoplastic transformation of guinea pig cells can, therefore, occur without formation of detectable, individually distinct cell surface tumor-specific neoantigens

Cancer Modeling: From Optimal Cell Renewal to Immunotherapy

Science.gov (United States)

Alvarado Alvarado, Cesar Leonardo

Cancer is a disease caused by mutations in normal cells. According to the National Cancer Institute, in 2016, an estimated 1.6 million people were diagnosed and approximately 0.5 million people died from the disease in the United States. There are many factors that shape cancer at the cellular and organismal level, including genetic, immunological, and environmental components. In this thesis, we show how mathematical modeling can be used to provide insight into some of the key mechanisms underlying cancer dynamics. First, we use mathematical modeling to investigate optimal homeostatic cell renewal in tissues such as the small intestine with an emphasis on division patterns and tissue architecture. We find that the division patterns that delay the accumulation of mutations are strictly associated with the population sizes of the tissue. In particular, patterns with long chains of differentiation delay the time to observe a second-hit mutant, which is important given that for many cancers two mutations are enough to initiate a tumor. We also investigated homeostatic cell renewal under a selective pressure and find that hierarchically organized tissues act as suppressors of selection; we find that an architecture with a small number of stem cells and larger pools of transit amplifying cells and mature differentiated cells, together with long chains of differentiation, form a robust evolutionary strategy to delay the time to observe a second-hit mutant when mutations acquire a fitness advantage or disadvantage. We also formulate a model of the immune response to cancer in the presence of costimulatory and inhibitory signals. We demonstrate that the coordination of such signals is crucial to initiate an effective immune response, and while immunotherapy has become a promising cancer treatment over the past decade, these results offer some explanations for why it can fail.

The combination of valproic acid and lithium delays hematopoietic stem/progenitor cell differentiation

NARCIS (Netherlands)

Walasek, Marta A.; Bystrykh, Leonid; van den Boom, Vincent; Olthof, Sandra; Ausema, Albertina; Ritsema, Martha; Huls, Gerwin; de Haan, Gerald; van Os, Ronald

2012-01-01

Despite increasing knowledge on the regulation of hematopoietic stem/progenitor cell (HSPC) self-renewal and differentiation, in vitro control of stem cell fate decisions has been difficult. The ability to inhibit HSPC commitment in culture may be of benefit to cell therapy protocols. Small

Mechanisms of glyceryl trinitrate provoked mast cell degranulation

DEFF Research Database (Denmark)

Pedersen, Sara Hougaard; Ramachandran, Roshni; Amrutkar, Dipak Vasantrao

2015-01-01

inflammation and dural mast cell degranulation is supported by the effectiveness of prednisolone on glyceryl trinitrate-induced delayed headache. METHODS: Using a newly developed rat model mimicking the human glyceryl trinitrate headache model, we have investigated the occurrence of dural mast cell...... glyceryl trinitrate-induced mast cell degranulation whereas the calcitonin gene-related peptide-receptor antagonist olcegepant and the substance P receptor antagonist L-733,060 did not affect mast cell degranulation. However, topical application of two different nitric oxide donors did not cause mast cell...... degranulation ex vivo. CONCLUSIONS: Direct application of an exogenous nitric oxide donor on dural mast cells does not cause mast cell degranulation ex vivo. In vivo application of the nitric oxide donor glyceryl trinitrate leads to a prominent level of degranulation via a yet unknown mechanism. This effect can...

Rapid Disease Progression With Delay in Treatment of Non-Small-Cell Lung Cancer

International Nuclear Information System (INIS)

Mohammed, Nasiruddin; Kestin, Larry Llyn; Grills, Inga Siiner; Battu, Madhu; Fitch, Dwight Lamar; Wong, Ching-yee Oliver; Margolis, Jeffrey Harold; Chmielewski, Gary William; Welsh, Robert James

2011-01-01

Purpose: To assess rate of disease progression from diagnosis to initiation of treatment for Stage I-IIIB non-small-cell lung cancer (NSCLC). Methods and Materials: Forty patients with NSCLC underwent at least two sets of computed tomography (CT) and 18-fluorodeoxyglucose positron emission tomography (PET) scans at various time intervals before treatment. Progression was defined as development of any new lymph node involvement, site of disease, or stage change. Results: Median time interval between first and second CT scans was 13.4 weeks, and between first and second PET scans was 9.0 weeks. Median initial primary maximum tumor dimension (MTD) was 3.5 cm (0.6-8.5 cm) with a median standardized uptake value (SUV) of 13.0 (1.7-38.5). The median MTD increased by a median of 1.0 cm (mean, 1.6 cm) between scans for a median relative MTD increase of 35% (mean, 59%). Nineteen patients (48%) progressed between scans. Rate of any progression was 13%, 31%, and 46% at 4, 8, and 16 weeks, respectively. Upstaging occurred in 3%, 13%, and 21% at these intervals. Distant metastasis became evident in 3%, 13%, and 13% after 4, 8, and 16 weeks, respectively. T and N stage were associated with progression, whereas histology, grade, sex, age, and maximum SUV were not. At 3 years, overall survival for Stage III patients with vs. without progression was 18% vs. 67%, p = 0.05. Conclusions: With NSCLC, treatment delay can lead to disease progression. Diagnosis, staging, and treatment initiation should be expedited. After 4-8 weeks of delay, complete restaging should be strongly considered.

Pharmacological Characterization of the Mechanisms Involved in Delayed Calcium Deregulation in SH-SY5Y Cells Challenged with Methadone

Directory of Open Access Journals (Sweden)

Sergio Perez-Alvarez

2012-01-01

Full Text Available Previously, we have shown that SH-SY5Y cells exposed to high concentrations of methadone died due to a necrotic-like cell death mechanism related to delayed calcium deregulation (DCD. In this study, we show that, in terms of their Ca2+ responses to 0.5 mM methadone, SH-SY5Y cells can be pooled into four different groups. In a broad pharmacological survey, the relevance of different Ca2+-related mechanisms on methadone-induced DCD was investigated including extracellular calcium, L-type Ca2+ channels, μ-opioid receptor, mitochondrial inner membrane potential, mitochondrial ATP synthesis, mitochondrial Ca2+/2Na+-exchanger, reactive oxygen species, and mitochondrial permeability transition. Only those compounds targeting mitochondria such as oligomycin, FCCP, CGP 37157, and cyclosporine A were able to amend methadone-induced Ca2+ dyshomeostasis suggesting that methadone induces DCD by modulating the ability of mitochondria to handle Ca2+. Consistently, mitochondria became dramatically shorter and rounder in the presence of methadone. Furthermore, analysis of oxygen uptake by isolated rat liver mitochondria suggested that methadone affected mitochondrial Ca2+ uptake in a respiratory substrate-dependent way. We conclude that methadone causes failure of intracellular Ca2+ homeostasis, and this effect is associated with morphological and functional changes of mitochondria. Likely, this mechanism contributes to degenerative side effects associated with methadone treatment.

MIF inhibition interferes with the inflammatory and T cell-stimulatory capacity of NOD macrophages and delays autoimmune diabetes onset.

Directory of Open Access Journals (Sweden)

Hannelie Korf

Full Text Available Macrophages contribute in the initiation and progression of insulitis during type 1 diabetes (T1D. However, the mechanisms governing their recruitment into the islets as well as the manner of retention and activation are incompletely understood. Here, we investigated a role for macrophage migration inhibitory factor (MIF and its transmembrane receptor, CD74, in the progression of T1D. Our data indicated elevated MIF concentrations especially in long-standing T1D patients and mice. Additionally, NOD mice featured increased MIF gene expression and CD74+ leukocyte frequencies in the pancreas. We identified F4/80+ macrophages as the main immune cells in the pancreas expressing CD74 and showed that MIF antagonism of NOD macrophages prevented their activation-induced cytokine production. The physiological importance was highlighted by the fact that inhibition of MIF delayed the onset of autoimmune diabetes in two different diabetogenic T cell transfer models. Mechanistically, macrophages pre-conditioned with the MIF inhibitor featured a refractory capacity to trigger T cell activation by keeping them in a naïve state. This study underlines a possible role for MIF/CD74 signaling pathways in promoting macrophage-mediated inflammation in T1D. As therapies directed at the MIF/CD74 pathway are in clinical development, new opportunities may be proposed for arresting T1D progression.

Liver sinusoidal endothelial cells induce immunosuppressive IL-10-producing Th1 cells via the Notch pathway.

Science.gov (United States)

Neumann, Katrin; Rudolph, Christine; Neumann, Christian; Janke, Marko; Amsen, Derk; Scheffold, Alexander

2015-07-01

Under homeostasis, liver sinusoidal endothelial cells (LSECs) shift intrahepatic T-cell responses towards tolerance. However, the role of LSECs in the regulation of T-cell-induced liver inflammation is less clear. Here, we studied the capacity of LSECs to modulate pro-inflammatory Th1-cell differentiation in mice. Using in vitro co-culture systems and subsequent cytokine analysis, we showed that LSECs induced high amounts of the anti-inflammatory cytokine IL-10 in developing Th1 cells. These LSEC-stimulated Th1 cells had no pro-inflammatory capacity in vivo but instead actively suppressed an inflammatory Th1-cell-induced delayed-type hypersensitivity reaction. Blockage of IL-10 signaling in vivo inhibited immunosuppressive activity of LSEC-stimulated Th1 cells. We identified the Notch pathway as a mechanism how LSECs trigger IL-10 expression in Th1 cells. LSECs expressed high levels of the Delta-like and Jagged family of Notch ligands and induced expression of the Notch target genes hes-1 and deltex-1 in Th1 cells. Blockade of Notch signaling selectively inhibited IL-10 induction in Th1 cells by LSECs. Our findings suggest that LSEC-induced IL-10 expression in Th1 cells via the Notch pathway may contribute to the control of hepatic inflammatory immune responses by induction of a self-regulatory mechanism in pro-inflammatory Th1 cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Immunologic effects of whole body ultraviolet (uv) irradiation. II. Defect in splenic adherent cell antigen presentation for stimulation of T cell proliferation

International Nuclear Information System (INIS)

Letvin, N.L.; Fox, I.J.; Greene, M.I.; Benacerraf, B.; Germain, R.N.

1980-01-01

Ultraviolet (uv) irradiation has been shown to alter many parameters of the immunologic reactivity of mice. The altered responsiveness of uv-irradiated mice, as measured by delayed-type hypersensitivity (DTH) and primary in vitro plaque-forming cell (PFC) responses to T-dependent antigens, has recently been correlated with a functional defect in the splenic adherent cell population of these animals. The present studies describe a model of this altered responsiveness, which allows further clarification of the effects of external uv irradiation on the splenic antigen-presenting cell (APC) in its interactions with T cells

Characterisation of the clinical and activated T cell response to repeat delayed-type hypersensitivity skin challenges in human subjects, with KLH and PPD, as a potential model to test T cell-targeted therapies.

Science.gov (United States)

Belson, Alexandra; Schmidt, Tim; Fernando, Disala; Hardes, Kelly; Scott, Nicola; Brett, Sara; Clark, Deborah; Oliveira, João Joaquim; Davis, Bill; McHugh, Simon; Stone, John

2016-05-01

To characterise the delayed-type hypersensitivity (DTH) skin reaction to repeated challenges of keyhole limpet hemocyanin (KLH) and tuberculin purified protein derivative (PPD) in healthy volunteers, as a potential model to test T cell-targeted investigational agents. Forty-nine subjects received either KLH, PPD, or PBS repeat skin challenges, and clinical assessments including induration, erythema and Laser Doppler Imaging. Skin biopsies or suction blisters were taken after challenge to investigate the cellular infiltrate of the challenge site, the T cell activation status, as determined by LAG-3 expression, and, specifically for the blister, the concentrations of inflammatory cytokines. Point estimates, estimates of variation and corresponding 95% confidence intervals were constructed for each type of challenge and timepoint. The DTH response could be measured at 48 and 120 h post-KLH and PPD challenge with induration, erythema and Laser Doppler Imaging, with 48 h post-challenge demonstrating the peak of the response. PPD was well tolerated in subjects after multiple challenges, however, a significant number of KLH-treated subjects demonstrated an injection site reaction 6-7 days following the SC injection. PPD demonstrated a boost effect on the second challenge as measured by increased induration, where as this was not noted consistently for KLH. Compared to unchallenged and PBS control-injected skin, increased T cell numbers were detected in the challenge site by both the skin suction blister and biopsy technique, at either time point following KLH or PPD challenge. Use of the T cell activation marker LAG-3 demonstrated the activated phenotype of these cells. In skin blisters, higher numbers of LAG-3+ T cells were detected at 48 h post-challenge, whereas in the biopsies, similar numbers of LAG-3+ cells were observed at both 48 and 120 h. Analysis of blister T cell subpopulations revealed some differences in phenotypes between the time points and between the CD4

Can Full Duplex Boost Throughput and Delay of 5G Ultra-Dense Small Cell Networks?

DEFF Research Database (Denmark)

Gatnau, Marta; Berardinelli, Gilberto; Mahmood, Nurul Huda

2016-01-01

Given the recent advances in system and antenna design, practical implementation of full duplex (FD) communication is becoming increasingly feasible. In this paper, the potential of FD in enhancing the performance of 5th generation (5G) ultra-dense small cell networks is investigated. The goal...... is to understand whether FD is able to boost the system performance from a throughput and delay perspective. The impact of having symmetric and asymmetric finite buffer traffic is studied for two types of FD: when only the base station is FD capable, and when both the user equipment and base station are FD nodes....... System level results indicate that there is a trade-off between multiple-input multiple-output (MIMO) spatial multiplexing and FD in achieving the optimal system performance. Moreover, results show that FD may be useful for asymmetric traffic applications where the lightly loaded link requires high level...

Sub-1-V-60 nm vertical body channel MOSFET-based six-transistor static random access memory array with wide noise margin and excellent power delay product and its optimization with the cell ratio on static random access memory cell

Science.gov (United States)

Ogasawara, Ryosuke; Endoh, Tetsuo

2018-04-01

In this study, with the aim to achieve a wide noise margin and an excellent power delay product (PDP), a vertical body channel (BC)-MOSFET-based six-transistor (6T) static random access memory (SRAM) array is evaluated by changing the number of pillars in each part of a SRAM cell, that is, by changing the cell ratio in the SRAM cell. This 60 nm vertical BC-MOSFET-based 6T SRAM array realizes 0.84 V operation under the best PDP and up to 31% improvement of PDP compared with the 6T SRAM array based on a 90 nm planar MOSFET whose gate length and channel width are the same as those of the 60 nm vertical BC-MOSFET. Additionally, the vertical BC-MOSFET-based 6T SRAM array achieves an 8.8% wider read static noise margin (RSNM), a 16% wider write margin (WM), and an 89% smaller leakage. Moreover, it is shown that changing the cell ratio brings larger improvements of RSNM, WM, and write time in the vertical BC-MOSFET-based 6T SRAM array.

Marijuana-derived Δ-9-tetrahydrocannabinol suppresses Th1/Th17 cell-mediated delayed-type hypersensitivity through microRNA regulation.

Science.gov (United States)

Sido, Jessica M; Jackson, Austin R; Nagarkatti, Prakash S; Nagarkatti, Mitzi

2016-09-01

∆(9)-Tetrahydrocannabinol (THC) is one of the major bioactive cannabinoids derived from the Cannabis sativa plant and is known for its anti-inflammatory properties. Delayed-type hypersensitivity (DTH) is driven by proinflammatory T helper cells including the classic inflammatory Th1 lineage as well as the more recently discovered Th17 lineage. In the current study, we investigated whether THC can alter the induction of Th1/Th17 cells involved in mBSA-induced DTH response. THC treatment (20 mg/kg) of C57BL/6 mice with DTH caused decreased swelling and infiltration of immune cells at the site of antigen rechallenge. Additionally, THC treatment decreased lymphocyte activation as well as Th1/Th17 lineage commitment, including reduced lineage-specific transcription factors and cytokines. Interestingly, while DTH caused an overexpression of miR-21, which increases Th17 differentiation via SMAD7 inhibition, and downregulation of miR-29b, an IFN-γ inhibitor, THC treatment reversed this microRNA (miR) dysregulation. Furthermore, when we transfected primary cells from DTH mice with miR-21 inhibitor or miR-29b mimic, as seen with THC treatment, the expression of target gene message was directly impacted increasing SMAD7 and decreasing IFN-γ expression, respectively. In summary, the current study suggests that THC treatment during DTH response can simultaneously inhibit Th1/Th17 activation via regulation of microRNA (miRNA) expression. • THC treatment inhibits simultaneous Th1/Th17 driven inflammation. • THC treatment corrects DTH-mediated microRNA dysregulation. • THC treatment regulates proinflammatory cytokines and transcription factors.

Zebrafish hair cell mechanics and physiology through the lens of noise-induced hair cell death

Science.gov (United States)

Coffin, Allison B.; Xu, Jie; Uribe, Phillip M.

2018-05-01

Hair cells are exquisitely sensitive to auditory stimuli, but also to damage from a variety of sources including noise trauma and ototoxic drugs. Mammals cannot regenerate cochlear hair cells, while non-mammalian vertebrates exhibit robust regenerative capacity. Our research group uses the lateral line system of larval zebrafish to explore the mechanisms underlying hair cell damage, identify protective therapies, and determine molecular drivers of innate regeneration. The lateral line system contains externally located sensory organs called neuromasts, each composed of ˜8-20 hair cells. Lateral line hair cells are homologous to vertebrate inner ear hair cells and share similar susceptibility to ototoxic damage. In the last decade, the lateral line has emerged as a powerful model system for understanding hair cell death mechanisms and for identifying novel protective compounds. Here we demonstrate that the lateral line is a tractable model for noise-induced hair cell death. We have developed a novel noise damage system capable of inducing over 50% loss of lateral line hair cells, with hair cell death occurring in a dose- and time-dependent manner. Cell death is greatest 72 hours post-exposure. However, early signs of hair cell damage, including changes in membrane integrity and reduced mechanotransduction, are apparent within hours of noise exposure. These features, early signs of damage followed by delayed hair cell death, are consistent with mammalian data, suggesting that noise acts similarly on zebrafish and mammalian hair cells. In our future work we will use our new model system to investigate noise damage events in real time, and to develop protective therapies for future translational research.

High glucose suppresses embryonic stem cell differentiation into neural lineage cells

OpenAIRE

Yang, Penghua; Shen, Wei-bin; Reece, E. Albert; Chen, Xi; Yang, Peixin

2016-01-01

Abnormal neurogenesis occurs during embryonic development in human diabetic pregnancies and in animal models of diabetic embryopathy. Our previous studies in a mouse model of diabetic embryopathy have implicated that high glucose of maternal diabetes delays neurogenesis in the developing neuroepithelium leading to neural tube defects. However, the underlying process in high glucose-impaired neurogenesis is uncharacterized. Neurogenesis from embryonic stem (ES) cells provides a valuable model ...

Targeting Senescent Cells : Possible Implications for Delaying Skin Aging: A Mini-Review

NARCIS (Netherlands)

Velarde, Michael C.; Demaria, Marco

2016-01-01

Senescent cells are induced by a wide variety of stimuli. They accumulate in several tissues during aging, including the skin. Senescent cells secrete proinflammatory cytokines, chemokines, growth factors, and proteases, a phenomenon called senescence-associated secretory phenotype (SASP), which are

Increased Arf/p53 activity in stem cells, aging and cancer.

Science.gov (United States)

Carrasco-Garcia, Estefania; Moreno, Manuel; Moreno-Cugnon, Leire; Matheu, Ander

2017-04-01

Arf/p53 pathway protects the cells against DNA damage induced by acute stress. This characteristic is the responsible for its tumor suppressor activity. Moreover, it regulates the chronic type of stress associated with aging. This is the basis of its anti-aging activity. Indeed, increased gene dosage of Arf/p53 displays elongated longevity and delayed aging. At a cellular level, it has been recently shown that increased dosage of Arf/p53 delays age-associated stem cell exhaustion and the subsequent decline in tissue homeostasis and regeneration. However, p53 can also promote aging if constitutively activated. In this context, p53 reduces tissue regeneration, which correlates with premature exhaustion of stem cells. We discuss here the current evidence linking the Arf/p53 pathway to the processes of aging and cancer through stem cell regulation. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

RNAi silenced Dd-grp94 (Dictyostelium discoideum glucose-regulated protein 94 kDa) cell lines in Dictyostelium exhibit marked reduction in growth rate and delay in development.

Science.gov (United States)

Baviskar, Sandhya N; Shields, Malcolm S

2010-01-01

Glucose-regulated 94 kDa protein (Grp94) is a resident of the endoplasmic reticulum (ER) of multicellular eukaryotes. It is a constitutively expressed protein that is overexpressed in certain abnormal conditions of the cell such as depletion of glucose and calcium, and low oxygen and pH. The protein is also implicated in diseased conditions like cancer and Alzheimer's disease. In this study, the consequences of downregulation of Grp94 were investigated at both unicellular and multicellular stages of Dictyostelium discoideum. Previous studies have shown the expression of Dd-Grp94 (Dictyostelium discoideum glucose-regulated 94 kDa protein) in wild-type cells varies during development, and overexpression of Dd-Grp94 leads to abnormal cell shape and inhibition of development (i.e., formation of fruiting bodies). Grp94 is a known calcium binding protein and an efficient calcium buffer. Therefore, in the present study we hypothesized that downregulation of Dd-Grp94 protein would affect Dictyostelium cell structure, growth, and development. We found that Dd-grp94 RNAi recombinants exhibited reduced growth rate, cell size, and a subtle change in cell motility compared to the parental cells. The recombinants also exhibited a delay in development and small fruiting bodies. These results establish that Dd-grp94 plays a crucial role in determining normal cell structure, growth and differentiation.

Whole tumor antigen vaccination using dendritic cells: Comparison of RNA electroporation and pulsing with UV-irradiated tumor cells

Directory of Open Access Journals (Sweden)

Benencia Fabian

2008-04-01

Full Text Available Abstract Because of the lack of full characterization of tumor associated antigens for solid tumors, whole antigen use is a convenient approach to tumor vaccination. Tumor RNA and apoptotic tumor cells have been used as a source of whole tumor antigen to prepare dendritic cell (DC based tumor vaccines, but their efficacy has not been directly compared. Here we compare directly RNA electroporation and pulsing of DCs with whole tumor cells killed by ultraviolet (UV B radiation using a convenient tumor model expressing human papilloma virus (HPV E6 and E7 oncogenes. Although both approaches led to DCs presenting tumor antigen, electroporation with tumor cell total RNA induced a significantly higher frequency of tumor-reactive IFN-gamma secreting T cells, and E7-specific CD8+ lymphocytes compared to pulsing with UV-irradiated tumor cells. DCs electroporated with tumor cell RNA induced a larger tumor infiltration by T cells and produced a significantly stronger delay in tumor growth compared to DCs pulsed with UV-irradiated tumor cells. We conclude that electroporation with whole tumor cell RNA and pulsing with UV-irradiated tumor cells are both effective in eliciting antitumor immune response, but RNA electroporation results in more potent tumor vaccination under the examined experimental conditions.

Relationships betwen mitotic delay and the dose rate of X radiation

International Nuclear Information System (INIS)

Yi, P.N.; Rha, C.K.; Evans, H.H.; Beer, J.Z.

1994-01-01

Upon exposure of cells to radiation delivered at a continuous low dose rate, cell proliferation may be sustained with the cells exhibiting a constant doubling time that is independent of the total dose. The doubling time or mitotic delay under these conditions has been shown to depend on the dose rate in HeLa, V79 and P388F cells. Reanalysis of the data for these particular cell lines shows that there is a threshold dose rate for mitotic delay, and that above the threshold there is a linear relationship between the length of mitotic delay and the logarithm of the dose rate which is referred to as the dose-rate response. We have observed the same relationships for L5178Y (LY)-R and LY-S cells exposed to low-dose-rate radiation. The threshold dose rates for LY-R, LY-S and P388F cells are similar (0.01-0.02 Gy/h) and are much lower than for V79 and HeLa cells. The slope of the dose-rate response curve is the greatest for HeLa cells, followed in order by LY-S, V79 and P388F cells, and finally by LY-R cells. The slopes for HeLa and LY-R cells differ by a factor of 35. 20 refs., 3 figs., 1 tab

Growth of human gastric cancer cells in nude mice is delayed by a ketogenic diet supplemented with omega-3 fatty acids and medium-chain triglycerides

International Nuclear Information System (INIS)

Otto, Christoph; Kaemmerer, Ulrike; Illert, Bertram; Muehling, Bettina; Pfetzer, Nadja; Wittig, Rainer; Voelker, Hans Ullrich; Thiede, Arnulf; Coy, Johannes F

2008-01-01

Among the most prominent metabolic alterations in cancer cells are the increase in glucose consumption and the conversion of glucose to lactic acid via the reduction of pyruvate even in the presence of oxygen. This phenomenon, known as aerobic glycolysis or the Warburg effect, may provide a rationale for therapeutic strategies that inhibit tumour growth by administration of a ketogenic diet with average protein but low in carbohydrates and high in fat enriched with omega-3 fatty acids and medium-chain triglycerides (MCT). Twenty-four female NMRI nude mice were injected subcutaneously with tumour cells of the gastric adenocarcinoma cell line 23132/87. The animals were then randomly split into two feeding groups and fed either a ketogenic diet (KD group; n = 12) or a standard diet (SD group; n = 12) ad libitum. Experiments were ended upon attainment of the target tumor volume of 600 mm 3 to 700 mm 3 . The two diets were compared based on tumour growth and survival time (interval between tumour cell injection and attainment of target tumour volume). The ketogenic diet was well accepted by the KD mice. The tumour growth in the KD group was significantly delayed compared to that in the SD group. Tumours in the KD group reached the target tumour volume at 34.2 ± 8.5 days versus only 23.3 ± 3.9 days in the SD group. After day 20, tumours in the KD group grew faster although the differences in mean tumour growth continued significantly. Importantly, they revealed significantly larger necrotic areas than tumours of the SD group and the areas with vital tumour cells appear to have had fewer vessels than tumours of the SD group. Viable tumour cells in the border zone surrounding the necrotic areas of tumours of both groups exhibited a glycolytic phenotype with expression of glucose transporter-1 and transketolase-like 1 enzyme. Application of an unrestricted ketogenic diet enriched with omega-3 fatty acids and MCT delayed tumour growth in a mouse xenograft model. Further

Growth of human gastric cancer cells in nude mice is delayed by a ketogenic diet supplemented with omega-3 fatty acids and medium-chain triglycerides

Directory of Open Access Journals (Sweden)

Voelker Hans

2008-04-01

Full Text Available Abstract Background Among the most prominent metabolic alterations in cancer cells are the increase in glucose consumption and the conversion of glucose to lactic acid via the reduction of pyruvate even in the presence of oxygen. This phenomenon, known as aerobic glycolysis or the Warburg effect, may provide a rationale for therapeutic strategies that inhibit tumour growth by administration of a ketogenic diet with average protein but low in carbohydrates and high in fat enriched with omega-3 fatty acids and medium-chain triglycerides (MCT. Methods Twenty-four female NMRI nude mice were injected subcutaneously with tumour cells of the gastric adenocarcinoma cell line 23132/87. The animals were then randomly split into two feeding groups and fed either a ketogenic diet (KD group; n = 12 or a standard diet (SD group; n = 12 ad libitum. Experiments were ended upon attainment of the target tumor volume of 600 mm3 to 700 mm3. The two diets were compared based on tumour growth and survival time (interval between tumour cell injection and attainment of target tumour volume. Results The ketogenic diet was well accepted by the KD mice. The tumour growth in the KD group was significantly delayed compared to that in the SD group. Tumours in the KD group reached the target tumour volume at 34.2 ± 8.5 days versus only 23.3 ± 3.9 days in the SD group. After day 20, tumours in the KD group grew faster although the differences in mean tumour growth continued significantly. Importantly, they revealed significantly larger necrotic areas than tumours of the SD group and the areas with vital tumour cells appear to have had fewer vessels than tumours of the SD group. Viable tumour cells in the border zone surrounding the necrotic areas of tumours of both groups exhibited a glycolytic phenotype with expression of glucose transporter-1 and transketolase-like 1 enzyme. Conclusion Application of an unrestricted ketogenic diet enriched with omega-3 fatty acids and MCT

Bioeffects of low-energy continuous ultrasound on isolated sarcoma 180 cells.

Science.gov (United States)

Wang, Xiaobing; Liu, Quanhong; Wang, Zhezhi; Wang, Pan; Hao, Qiao; Li, Chendi

2009-01-01

The aim of this study was to investigate the mechanism underlying bioeffects of low-intensity continuous ultrasound on isolated sarcoma 180 (S180) cells and cellular responses to these effects. After sonication, several structural and functional parameters were examined to elucidate ultrasound-induced cell damage. Instant disruption of the cell membrane might be caused by acoustic cavitation, producing mechanical and chemical effects that acted simultaneously on S180 cells; this could be reflected by immediate (morphological) changes such as membrane permeability, membrane fluidity, lipid peroxidation and the generation of hydroxyl radicals in culture medium. Our results of the delayed effects also indicated S180 cells were sensitive to ultrasound-induced apoptosis, and the rate of apoptosis rose gradually with a prolonged incubation time. The presence of apoptotic cells was identified by a distinct morphological form characterized by membrane blebbing, cell shrinkage, chromatin condensation and DNA fragmentation. Moreover, delayed cytotoxicity was accompanied by an increase in intracellular reactive oxygen species (ROS) and a decrease in the mitochondrial membrane potential, and the two events presented obviously a negative correlation. ROS secondarily generated from damaged mitochondria may play a role in the induction of apoptosis. Copyright 2009 S. Karger AG, Basel.

Effect of ranitidine on postoperative suppression of natural killer cell activity and delayed hypersensitivity

DEFF Research Database (Denmark)

Nielsen, Hans Jørgen; Pedersen, B K; Moesgaard, F

1989-01-01

hypersensitivity (DTH) antigens, and blood drawn immediately before and 24 hours after skin incision was analyzed for spontaneous and in vitro stimulated (IL-2, IFN-alpha or indomethacin) natural killer (NK) cell activity and PHA and PPD-stimulated lymphocyte proliferation. Lymphocyte subsets (helper......-cell activity (p less than 0.02). Postoperative decrease in helper/inducer-T cell numbers was not significantly lessened (p = 0.07), and ranitidine did not influence the levels of suppressor-T cells. PHA and PPD responses in peripheral blood mononuclear cells were unaltered. The results may suggest potential...

Bystander responses in three-dimensional cultures containing radiolabelled and unlabelled human cells

International Nuclear Information System (INIS)

Pinto, M.; Azzam, E. I.; Howell, R. W.

2006-01-01

Research on the radiation-induced bystander effect has been carried out mainly in 2-D tissue culture systems. This study uses a 3-D model, wherein apparently normal human diploid fibroblasts (AG1522) are grown in a carbon scaffold, to investigate the induction of a G 1 checkpoint in bystander cells present alongside radiolabelled cells. Cultures were simultaneously pulse-labelled with 3 H-deoxycytidine ( 3 HdC) to selectively irradiate a minor fraction of cells, and bromodeoxyuridine (BrdU) to identify the radiolabelled cells. After thorough washing of cultures, iododeoxyuridine (IdU) was administered to detect proliferating bystander cells. The cultures were harvested at various times thereafter, and cells were reacted with two monoclonal antibodies specific to IdU/BrdU or BrdU, respectively, stained with propidium iodide, and subjected to multi-parameter flow cytometry. Cell-cycle progression was followed in radiolabelled cells (BrdU + ) that were chronically irradiated by low energy beta particles emitted by DNA-incorporated 3 H, and in unlabelled bystander cells (BrdU - ) by a flow cytometry based cumulative labelling index assay. As expected, radiolabelled cells were delayed, in a dose-dependent manner, in G 2 and subsequently G 1 . No delay occurred in progression of bystander cells through G 1 , when the labelled cells were irradiated at dose rates up to 0.32 Gy h -1 . (authors)

Human neutrophils facilitate tumor cell transendothelial migration.

LENUS (Irish Health Repository)

Wu, Q D

2012-02-03

Tumor cell extravasation plays a key role in tumor metastasis. However, the precise mechanisms by which tumor cells migrate through normal vascular endothelium remain unclear. In this study, using an in vitro transendothelial migration model, we show that human polymorphonuclear neutrophils (PMN) assist the human breast tumor cell line MDA-MB-231 to cross the endothelial barrier. We found that tumor-conditioned medium (TCM) downregulated PMN cytocidal function, delayed PMN apoptosis, and concomitantly upregulated PMN adhesion molecule expression. These PMN treated with TCM attached to tumor cells and facilitated tumor cell migration through different endothelial monolayers. In contrast, MDA-MB-231 cells alone did not transmigrate. FACScan analysis revealed that these tumor cells expressed high levels of intercellular adhesion molecule-1 (ICAM-1) but did not express CD11a, CD11b, or CD18. Blockage of CD11b and CD18 on PMN and of ICAM-1 on MDA-MB-231 cells significantly attenuated TCM-treated, PMN-mediated tumor cell migration. These tumor cells still possessed the ability to proliferate after PMN-assisted transmigration. These results indicate that TCM-treated PMN may serve as a carrier to assist tumor cell transendothelial migration and suggest that tumor cells can exploit PMN and alter their function to facilitate their extravasation.

Cancer cell uptake behavior of Au nanoring and its localized surface plasmon resonance induced cell inactivation

International Nuclear Information System (INIS)

Chu, Che-Kuan; Tu, Yi-Chou; Chang, Yu-Wei; Chu, Chih-Ken; Chen, Shih-Yang; Chi, Ting-Ta; Kiang, Yean-Woei; Yang, Chih-Chung

2015-01-01

Au nanorings (NRIs), which have the localized surface plasmon resonance (LSPR) wavelength around 1058 nm, either with or without linked antibodies, are applied to SAS oral cancer cells for cell inactivation through the LSPR-induced photothermal effect when they are illuminated by a laser of 1065 nm in wavelength. Different incubation times of cells with Au NRIs are considered for observing the variations of cell uptake efficiency of Au NRI and the threshold laser intensity for cell inactivation. In each case of incubation time, the cell sample is washed for evaluating the total Au NRI number per cell adsorbed and internalized by the cells based on inductively coupled plasma mass spectrometry measurement. Also, the Au NRIs remaining on cell membrane are etched with KI/I 2 solution to evaluate the internalized Au NRI number per cell. The threshold laser intensities for cell inactivation before washout, after washout, and after KI/I 2 etching are calibrated from the circular area sizes of inactivated cells around the illuminated laser spot center with various laser power levels. By using Au NRIs with antibodies, the internalized Au NRI number per cell increases monotonically with incubation time up to 24 h. However, the number of Au NRI remaining on cell membrane reaches a maximum at 12 h in incubation time. The cell uptake behavior of an Au NRI without antibodies is similar to that with antibodies except that the uptake NRI number is significantly smaller and the incubation time for the maximum NRI number remaining on cell membrane is delayed to 20 h. By comparing the threshold laser intensities before and after KI/I 2 etching, it is found that the Au NRIs remaining on cell membrane cause more effective cancer cell inactivation, when compared with the internalized Au NRIs. (paper)

Differential expression of conserved germ line markers and delayed segregation of male and female primordial germ cells in a hermaphrodite, the leech helobdella.

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Cho, Sung-Jin; Vallès, Yvonne; Weisblat, David A

2014-02-01

In sexually reproducing animals, primordial germ cells (PGCs) are often set aside early in embryogenesis, a strategy that minimizes the risk of genomic damage associated with replication and mitosis during the cell cycle. Here, we have used germ line markers (piwi, vasa, and nanos) and microinjected cell lineage tracers to show that PGC specification in the leech genus Helobdella follows a different scenario: in this hermaphrodite, the male and female PGCs segregate from somatic lineages only after more than 20 rounds of zygotic mitosis; the male and female PGCs share the same (mesodermal) cell lineage for 19 rounds of zygotic mitosis. Moreover, while all three markers are expressed in both male and female reproductive tissues of the adult, they are expressed differentially between the male and female PGCs of the developing embryo: piwi and vasa are expressed preferentially in female PGCs at a time when nanos is expressed preferentially in male PGCs. A priori, the delayed segregation of male and female PGCs from somatic tissues and from one another increases the probability of mutations affecting both male and female PGCs of a given individual. We speculate that this suite of features, combined with a capacity for self-fertilization, may contribute to the dramatically rearranged genome of Helobdella robusta relative to other animals.

Present and future of allogeneic natural killer cell therapy

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Okjae eLim

2015-06-01

Full Text Available Natural killer (NK cells are innate lymphocytes that are capable of eliminating tumor cells and are therefore used for cancer therapy. Although many early investigators used autologous NK cells, including lymphokine-activated killer cells, the clinical efficacies were not satisfactory. Meanwhile, human leukocyte antigen (HLA-haploidentical hematopoietic stem cell transplantation revealed the anti-tumor effect of allogeneic NK cells, and HLA-haploidentical, killer cell immunoglobulin-like receptor (KIR ligand-mismatched allogeneic NK cells are currently used for many protocols requiring NK cells. Moreover, allogeneic NK cells from non-HLA-related healthy donors have been recently used in cancer therapy. The use of allogeneic NK cells from non-HLA-related healthy donors allows the selection of donor NK cells with higher flexibility and to prepare expanded, cryopreserved NK cells for instant administration without delay for ex vivo expansion. In cancer therapy with allogeneic NK cells, optimal matching of donors and recipients is important to maximize the efficacy of the therapy. In this review, we summarize the present state of allogeneic NK cell therapy and its future directions.

Multiple intracerebroventricular injections of human umbilical cord mesenchymal stem cells delay motor neurons loss but not disease progression of SOD1G93A mice.

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Sironi, Francesca; Vallarola, Antonio; Violatto, Martina Bruna; Talamini, Laura; Freschi, Mattia; De Gioia, Roberta; Capelli, Chiara; Agostini, Azzurra; Moscatelli, Davide; Tortarolo, Massimo; Bigini, Paolo; Introna, Martino; Bendotti, Caterina

2017-12-01

Stem cell therapy is considered a promising approach in the treatment of amyotrophic lateral sclerosis (ALS) and mesenchymal stem cells (MSCs) seem to be the most effective in ALS animal models. The umbilical cord (UC) is a source of highly proliferating fetal MSCs, more easily collectable than other MSCs. Recently we demonstrated that human (h) UC-MSCs, double labeled with fluorescent nanoparticles and Hoechst-33258 and transplanted intracerebroventricularly (ICV) into SOD1G93A transgenic mice, partially migrated into the spinal cord after a single injection. This prompted us to assess the effect of repeated ICV injections of hUC-MSCs on disease progression in SOD1G93A mice. Although no transplanted cells migrated to the spinal cord, a partial but significant protection of motor neurons (MNs) was found in the lumbar spinal cord of hUC-MSCs-treated SOD1G93A mice, accompanied by a shift from a pro-inflammatory (IL-6, IL-1β) to anti-inflammatory (IL-4, IL-10) and neuroprotective (IGF-1) environment in the lumbar spinal cord, probably linked to the activation of p-Akt survival pathway in both motor neurons and reactive astrocytes. However, this treatment neither prevented the muscle denervation nor delayed the disease progression of mice, emphasizing the growing evidence that protecting the motor neuron perikarya is not sufficient to delay the ALS progression. Copyright © 2017. Published by Elsevier B.V.

Anti-M causing delayed hemolytic transfusion reaction

International Nuclear Information System (INIS)

Alperin, J.B.; Riglin, H.; Branch, D.R.; Gallagher, M.T.; Petz, L.D.

1983-01-01

A 52-year-old gravida 1, para 1 woman with M- red cells experienced a delayed hemolytic transfusion reaction and exhibited an anti-M antibody following the infusion of four units of M+ red cells. Measurements of erythrocyte survival using 51 Cr-labeled donor M+ and M- red cells and in vitro studies of monocyte-macrophage phagocytosis of sensitized reagent red cells implicate anti-M in the pathogenesis of hemolysis

Computer battery cell in the cricopharynx of a toddler

OpenAIRE

Majumdar, Aloke Bose; Sengupta, Arup; Pal, Ranabir

2011-01-01

A computer lithium battery cell was impacted in the cricopharynx of a 1 year and 9 month-old child. The battery cell was safely removed with the pediatric flexible oesophagoscope under anesthesia without trauma to the surrounding structures. The lithium battery cell is potentially dangerous due to its ability to cause chemical damage to the mucosa and cause early inflammation and edema leading to dysphagia and respiratory obstruction. Hence, it should be promptly extracted without delay to pr...

Comparison of γ i-irradiation-induced accumulation of ataxia telangiesctasia and control cells in G2 phase

International Nuclear Information System (INIS)

Bates, P.R.; Lavin, M.F.

1989-01-01

Recent reports from a number of laboratories have linked radiosensitivity in ataxia telangiectasia (AT) to a large and prolonged block of some cells in G 2 phase. Previous results from this laboratory, largely with one Epstein-Barr virus-transformed A-T lymphoblastoid cell line, presented evidence for a dramatic increase in the number of cells in G 2 phase over controls during a 24 h period post irradiation. We describe here a study of the effect of γ-radiation on G 2 phase delay in several A-T cell lines. Based on previous results with several cell lines 24 h post irradiation was selected as the optimum time to discriminate between G 2 phase delay in control and A-T cells. All A-T homozygotes showed a signigicantly greater number of cells in G 2 phase, 24 h post irradiation, than observed in controls. A more prolonged delay in G 2 phase after irradiation was seen in different A-T cell types that included lymphoblastoid cells, fibroblasts and SV40-transformed fibroblasts. At the radiation dose used it was not possibel to distinguish A-T heterozygotes from controls (Author). 28 refs.; 2 figs.; 1 tab

Observations of the first postirradiation division of HeLa cells following continuous or fractionated exposure to γ rays

International Nuclear Information System (INIS)

Mitchell, J.B.; Bedford, J.S.; Bailey, S.M.

1979-01-01

The first postirradiation division of synchronized S3 HeLa cells was studied using both continuous and fractionated irradiation treatments. Synchronized HeLa cells continuously irradiated at a dose rate of 37 rad/hr eventually accumulate in mitosis. If the continuous irradiation is stopped before the cells enter G2 or even after they have progressed for a limited time into the G2 arrest that develops, very little subsequent accumulation of cells in mitosis occurs. If they progress for a longer time into the G2 arrest, then some mitotic accumulation does occur after the irradiation is stopped. When synchronized cells were allowed to progress through G1 and S before the irradiation was started, very little cell division occurred during subsequent continuous irradiation and extensive mitotic accumulation was observed. Thus, for continuous irradiation of HeLa cells, the dose received by a cell during G2 or a G2 delay apparently determines whether it will be able to divide if it reaches mitosis. Arguing against the notion that continuous irradiation during G2 is required to produce a mitotic accumulation was the result of an expriment which showed that a similar effect was obtained using two acute doses: the first to produce a G2 delay and the second to give the necessary dose during the delay. The first dose alone resulted in little mitotic accumulation. The time of delivery of the second dose during the G2 delay affected the extent of mitotic accumulation observed. There was less mitotic accumulation when second acute doses were given early or at intermediate times during the delay than when they were given late during the G2 delay. An accumulation of cells in mitosis was also observed by using a combination of low-dose-rate irradiation to induce a G2 delay, followed immediately by an acute dose of either 500 or 1000 rad. The low-dose-rate treatment alone resulted in no mitotic accumulation

Low-level radiation effects on immune cells

International Nuclear Information System (INIS)

Makinodan, T.

1995-01-01

The purpose of this study was to characterize the effects of chronic low-dose ionizing radiation (LDR) on murine immune cells. Previously, it had been reported that LDR enhances the proliferative activity of T cells in vitro and delays the growth of transplantable immunogenic tumors in vivo. This suggests that LDR eliminates immune suppressor cells, which downregulates immune response and/or adoptively upregulates the responsiveness of immune effector cells. It had also been reported that human lymphocytes become refractive to high dose radiation-induced chromosomal aberrations by pretreating mitotically active lymphocytes in vitro with very low doses of ionizing radiation, and the adaptive effect can be abrogated by cycloheximide. This suggests that protein synthesis is required for lymphocytes to respond adoptively to LDR

Delayed nerve stimulation promotes axon-protective neurofilament phosphorylation, accelerates immune cell clearance and enhances remyelination in vivo in focally demyelinated nerves.

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Nikki A McLean

Full Text Available Rapid and efficient axon remyelination aids in restoring strong electrochemical communication with end organs and in preventing axonal degeneration often observed in demyelinating neuropathies. The signals from axons that can trigger more effective remyelination in vivo are still being elucidated. Here we report the remarkable effect of delayed brief electrical nerve stimulation (ES; 1 hour @ 20 Hz 5 days post-demyelination on ensuing reparative events in a focally demyelinated adult rat peripheral nerve. ES impacted many parameters underlying successful remyelination. It effected increased neurofilament expression and phosphorylation, both implicated in axon protection. ES increased expression of myelin basic protein (MBP and promoted node of Ranvier re-organization, both of which coincided with the early reappearance of remyelinated axons, effects not observed at the same time points in non-stimulated demyelinated nerves. The improved ES-associated remyelination was accompanied by enhanced clearance of ED-1 positive macrophages and attenuation of glial fibrillary acidic protein expression in accompanying Schwann cells, suggesting a more rapid clearance of myelin debris and return of Schwann cells to a nonreactive myelinating state. These benefits of ES correlated with increased levels of brain derived neurotrophic factor (BDNF in the acute demyelination zone, a key molecule in the initiation of the myelination program. In conclusion, the tremendous impact of delayed brief nerve stimulation on enhancement of the innate capacity of a focally demyelinated nerve to successfully remyelinate identifies manipulation of this axis as a novel therapeutic target for demyelinating pathologies.

Delayed nerve stimulation promotes axon-protective neurofilament phosphorylation, accelerates immune cell clearance and enhances remyelination in vivo in focally demyelinated nerves.

Science.gov (United States)

McLean, Nikki A; Popescu, Bogdan F; Gordon, Tessa; Zochodne, Douglas W; Verge, Valerie M K

2014-01-01

Rapid and efficient axon remyelination aids in restoring strong electrochemical communication with end organs and in preventing axonal degeneration often observed in demyelinating neuropathies. The signals from axons that can trigger more effective remyelination in vivo are still being elucidated. Here we report the remarkable effect of delayed brief electrical nerve stimulation (ES; 1 hour @ 20 Hz 5 days post-demyelination) on ensuing reparative events in a focally demyelinated adult rat peripheral nerve. ES impacted many parameters underlying successful remyelination. It effected increased neurofilament expression and phosphorylation, both implicated in axon protection. ES increased expression of myelin basic protein (MBP) and promoted node of Ranvier re-organization, both of which coincided with the early reappearance of remyelinated axons, effects not observed at the same time points in non-stimulated demyelinated nerves. The improved ES-associated remyelination was accompanied by enhanced clearance of ED-1 positive macrophages and attenuation of glial fibrillary acidic protein expression in accompanying Schwann cells, suggesting a more rapid clearance of myelin debris and return of Schwann cells to a nonreactive myelinating state. These benefits of ES correlated with increased levels of brain derived neurotrophic factor (BDNF) in the acute demyelination zone, a key molecule in the initiation of the myelination program. In conclusion, the tremendous impact of delayed brief nerve stimulation on enhancement of the innate capacity of a focally demyelinated nerve to successfully remyelinate identifies manipulation of this axis as a novel therapeutic target for demyelinating pathologies.

Synergistic Inhibition of Delayed Rectifier K+ and Voltage-Gated Na+ Currents by Artemisinin in Pituitary Tumor (GH3) Cells.

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So, Edmund Cheung; Wu, Sheng-Nan; Wu, Ping-Ching; Chen, Hui-Zhen; Yang, Chia-Jung

2017-01-01

Artemisinin (ART) is an anti-malarial agent reported to influence endocrine function. Effects of ART on ionic currents and action potentials (APs) in pituitary tumor (GH3) cells were evaluated by patch clamp techniques. ART inhibited the amplitude of delayed-rectifier K+ current (IK(DR)) in response to membrane depolarization and accelerated the process of current inactivation. It exerted an inhibitory effect on IK(DR) with an IC50 value of 11.2 µM and enhanced IK(DR) inactivation with a KD value of 14.7 µM. The steady-state inactivation curve of IK(DR) was shifted to hyperpolarization by 10 mV. Pretreatment of chlorotoxin (1 µM) or iloprost (100 nM) did not alter the magnitude of ART-induced inhibition of IK(DR) in GH3 cells. ART also decreased the peak amplitude of voltage-gated Na+ current (INa) with a concentration-dependent slowing in inactivation rate. Application of KMUP-1, an inhibitor of late INa, was effective at reversing ART-induced prolongation in inactivation time constant of INa. Under current-clamp recordings, ART alone reduced the amplitude of APs and prolonged the duration of APs. Under ART exposure, the inhibitory actions on both IK(DR) and INa could be a potential mechanisms through which this drug influences membrane excitability of endocrine or neuroendocrine cells appearing in vivo. © 2017 The Author(s). Published by S. Karger AG, Basel.

Acacetin enhances the therapeutic efficacy of doxorubicin in non-small-cell lung carcinoma cells.

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Reenu Punia

Full Text Available Anthracyclines are efficient and potent agents to treat broad range of cancers but cytotoxicity induced by them limits their use in therapeutics. Use of plant-derived agents help to prevent or delay the process of cancer progression and their combination increases the anti-cancer potential of mainstream compound. However, multidrug resistance is major cause of treatment failure in cancer patients.In this study, combination treatments of fisetin or acacetin with doxorubicin were explored for their potential synergistic effect on non-small-cell lung carcinoma (NSCLC cells.During this study, NSCLC model cell lines A549 and H1299 were used to determine the combinatorial effect of phytochemicals namly acacetin and fisetin with doxorubicin.The effects of individual compounds and their combination on cell viability, clonogenic potential and cell cycle progression were studied. Efflux of doxorubicin was measured by spectrofluorophotometer, whereas accumulation inside the cells was analyzed by flow cytometry and confocal microscopy. Expression of MDR1 was checked by semi-quantitative PCR.The results showed that the cell viability of A549 and H1299 cells were significantly decreased in time- and dose-dependent manner, although A549 cells showed more sensitivity toward doxorubicin than H1299 cells. Mostly, combination of doxorubicin showed good synergy with acacetin in both the cell lines whereas, fisetin exerted synergistic effect only at 72 h of treatment in H1299 cells. Acacetin with doxorubicin caused G2/M arrest by downregulating CDK-cyclin complex in A549 cells. Acacetin-doxorubicin combination decreased the clonogenic potential of A549 and H1299 cells upto 82% and 59%, respectively, as compared to control. Acacetin also decreased efflux of doxorubicin by 59% after 30 mins of exposure to A549 cells and further increased accumulation of doxorubicin inside the cells upto 55% in 2 h. The modulatory effect of acacetin-doxorubicin combination on

Radiolabelling of sperm cells with 99mTc-HMPAO. In vivo visualization of sperm cell migration in rabbits

International Nuclear Information System (INIS)

Bockisch, A.; Tennessee Univ., Knoxville, TN; Tennessee Univ., Knoxville, TN; Al-Hasani, S.; Ven, H.V.D.; Diedrich, K.; Krebs, D.; Posch, C.; Hotze, A.; Biersack, H.J.

1989-01-01

The present paper is the first descriptive radiolabeling of sperm cells in order to visualize their in vivo migration and imaging by scintigraphic technique, 99m Tc-HMPAO was used which combines favourable characteristics of both imaging modalities and radiation exposure. The radiolabeling yield was optimised for human sperm cells, and was increasing with the number of sperm cells, the amount of HMPAO, the 99m Tc-HMPAO concentration and the duration of the incubation. Incubation periods greater than 20 min, however, resulted only in a minor increase of labeling yield. A delay of more than 5 min between the labeling of the HMPAO with 99m Tc and initiation of the incubation of the sperm cells with the 99m Tc-HMPAO also decreased the maximum labeling yield. The radiolabeled cells were found to be stable and after 18 h > 93% of the activity was still bound to the sperm cells. After insemination of labeled sperm cells in ovulating rabbits the accumulation of the cells in the Fallopian tubes and their subsequent migration could be clearly visualized by scintigraphic techniques in vivo. (orig.) [de

Nimotuzumab promotes radiosensitivity of EGFR-overexpression esophageal squamous cell carcinoma cells by upregulating IGFBP-3

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Zhao Lei

2012-12-01

Full Text Available Abstract Background Epidermal growth factor receptor (EGFR is suggested to predict the radiosensitivity and/or prognosis of human esophageal squamous cell carcinoma (ESCC. The objective of this study was to investigate the efficacy of Nimotuzumab (an anti-EGFR monoclonal antibody on ESCC radiotherapy (RT and underlying mechanisms. Methods Nimotuzumab was administrated to 2 ESCC cell lines KYSE30 and TE-1 treated with RT. Cell growth, colony formation and apoptosis were used to measure anti-proliferation effects. The method of RNA interference was used to investigate the role of insulin-like growth factor binding protein-3 (IGFBP-3 in ESCC cells radiosensitivity treated with Nimotuzumab. In vivo effect of Nimotuzumab on ESCC radiotherapy was done using a mouse xenograft model. Results Nimotuzumab enhanced radiation response of KYSE30 cells (with high EGFR expression in vitro, as evidenced by increased radiation-inhibited cell growth and colony formation and radiation-mediated apoptosis. Mechanism study revealed that Nimotuzumab inhibited phosphorylated EGFR (p-EGFR induced by EGF in KYSE30 cells. In addition, knockdown of IGFBP-3 by short hairpin RNA significantly reduced KYSE30 cells radiosensitivity (PP>0.05. In KYSE30 cell xenografts, Nimotuzumab combined with radiation led to significant tumor growth delay, compared with that of radiation alone (P=0.029, and also with IGFBP-3 up-regulation in tumor tissue. Conclusions Nimotuzumab could enhance the RT effect of ESCC cells with a functional active EGFR pathway. In particular, the increased ESCC radiosensitivity by Nimotuzumab might be dependent on the up-regulation of IGFBP-3 through EGFR-dependent pathway.

Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays

International Nuclear Information System (INIS)

Bi, Ping; Ruan, Shigui; Zhang, Xinan

2014-01-01

In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical values and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations

Regulatory T cells ameliorate tissue plasminogen activator-induced brain haemorrhage after stroke.

Science.gov (United States)

Mao, Leilei; Li, Peiying; Zhu, Wen; Cai, Wei; Liu, Zongjian; Wang, Yanling; Luo, Wenli; Stetler, Ruth A; Leak, Rehana K; Yu, Weifeng; Gao, Yanqin; Chen, Jun; Chen, Gang; Hu, Xiaoming

2017-07-01

Delayed thrombolytic treatment with recombinant tissue plasminogen activator (tPA) may exacerbate blood-brain barrier breakdown after ischaemic stroke and lead to lethal haemorrhagic transformation. The immune system is a dynamic modulator of stroke response, and excessive immune cell accumulation in the cerebral vasculature is associated with compromised integrity of the blood-brain barrier. We previously reported that regulatory T cells, which function to suppress excessive immune responses, ameliorated blood-brain barrier damage after cerebral ischaemia. This study assessed the impact of regulatory T cells in the context of tPA-induced brain haemorrhage and investigated the underlying mechanisms of action. The number of circulating regulatory T cells in stroke patients was dramatically reduced soon after stroke onset (84 acute ischaemic stroke patients with or without intravenous tPA treatment, compared to 115 age and gender-matched healthy controls). Although stroke patients without tPA treatment gradually repopulated the numbers of circulating regulatory T cells within the first 7 days after stroke, post-ischaemic tPA treatment led to sustained suppression of regulatory T cells in the blood. We then used the murine suture and embolic middle cerebral artery occlusion models of stroke to investigate the therapeutic potential of adoptive regulatory T cell transfer against tPA-induced haemorrhagic transformation. Delayed administration of tPA (10 mg/kg) resulted in haemorrhagic transformation in the ischaemic territory 1 day after ischaemia. When regulatory T cells (2 × 106/mouse) were intravenously administered immediately after delayed tPA treatment in ischaemic mice, haemorrhagic transformation was significantly decreased, and this was associated with improved sensorimotor functions. Blood-brain barrier disruption and tight junction damages were observed in the presence of delayed tPA after stroke, but were mitigated by regulatory T cell transfer. Mechanistic

Model of inter-cell interference phenomenon in 10 nm magnetic tunnel junction with perpendicular anisotropy array due to oscillatory stray field from neighboring cells

Science.gov (United States)

Ohuchida, Satoshi; Endoh, Tetsuo

2018-06-01

In this paper, we propose a new model of inter-cell interference phenomenon in a 10 nm magnetic tunnel junction with perpendicular anisotropy (p-MTJ) array and investigated the interference effect between a program cell and unselected cells due to the oscillatory stray field from neighboring cells by Landau–Lifshitz–Gilbert micromagnetic simulation. We found that interference brings about a switching delay in a program cell and excitation of magnetization precession in unselected cells even when no programing current passes through. The origin of interference is ferromagnetic resonance between neighboring cells. During the interference period, the precession frequency of the program cell is 20.8 GHz, which synchronizes with that of the theoretical precession frequency f = γH eff in unselected cells. The disturbance strength of unselected cells decreased to be inversely proportional to the cube of the distance from the program cell, which is in good agreement with the dependence of stray field on the distance from the program cell calculated by the dipole approximation method.

Effect of glucocorticoids and gamma radiation on epidermal Langerhans cells

International Nuclear Information System (INIS)

Belsito, D.V.; Baer, R.L.; Thorbecke, G.J.; Gigli, I.

1984-01-01

The effect of 750 rads of gamma radiation on the rate of return of epidermal Langerhans cells (LC) following suppressive doses of topical glucorticoids was studied in guinea pigs. Gamma radiation alone had no effect on the LC as assessed by staining for cell membrane ATPase activity and Ia antigen. It did, however, delay the expected return of Ia but not ATPase surface markers on the LC after perturbation with glucocorticoids. The delayed return of surface Ia antigen is possibly related to a radiation-induced defect in the production of a required lymphokine and/or in intracellular Ia transport. Although our data do not rule out a cytolytic effect of steroids on the LC, they do strongly suggest that, at least in part, glucocorticoids act on the LC by altering cell surface characteristics

Pathogenesis of herpes simplex virus in B cell-suppressed mice: the relative roles of cell-mediated and humoral immunity.

Science.gov (United States)

Kapoor, A K; Nash, A A; Wildy, P

1982-07-01

B cell responses of Balb/c mice were suppressed using sheep anti-mouse IgM serum. At 4 weeks, both B cell-suppressed and normal littermates were infected in the ear pinna with herpes simplex virus type 1 (HSV-1). The B cell-suppressed mice failed to produce neutralizing herpes antibodies in their sera but had a normal cell-mediated immunity (CMI) response as measured by a delayed hypersensitivity skin test. Although the infection was eliminated from the ear in both B cell-suppressed and normal mice by day 10 after infection, there was an indication that B cell-suppressed mice had a more florid primary infection of the peripheral and central nervous system and also a higher incidence of a latent infection. These results support the hypothesis that antibody is important in restricting the spread of virus to the central nervous system, whereas CMI is important in clearing the primary infection in the ear pinna.

The Arabidopsis synaptotagmin SYTA regulates the cell-to-cell movement of diverse plant viruses

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Asako eUchiyama

2014-11-01

Full Text Available Synaptotagmins are a large gene family in animals that have been extensively characterized due to their role as calcium sensors to regulate synaptic vesicle exocytosis and endocytosis in neurons, and dense core vesicle exocytosis for hormone secretion from neuroendocrine cells. Thought to be exclusive to animals, synaptotagmins have recently been characterized in Arabidopsis thaliana, in which they comprise a five gene family. Using infectivity and leaf-based functional assays, we have shown that Arabidopsis SYTA regulates endocytosis and marks an endosomal vesicle recycling pathway to regulate movement protein-mediated trafficking of the Begomovirus Cabbage leaf curl virus (CaLCuV and the Tobamovirus Tobacco mosaic virus (TMV through plasmodesmata (Lewis and Lazarowitz, 2010. To determine whether SYTA has a central role in regulating the cell-to-cell trafficking of a wider range of diverse plant viruses, we extended our studies here to examine the role of SYTA in the cell-to-cell movement of additional plant viruses that employ different modes of movement, namely the Potyvirus Turnip mosaic virus (TuMV, the Caulimovirus Cauliflower mosaic virus (CaMV and the Tobamovirus Turnip vein clearing virus (TVCV, which in contrast to TMV does efficiently infect Arabidopsis. We found that both TuMV and TVCV systemic infection, and the cell-to-cell trafficking of the their movement proteins, were delayed in the Arabidopsis Col-0 syta-1 knockdown mutant. In contrast, CaMV systemic infection was not inhibited in syta-1. Our studies show that SYTA is a key regulator of plant virus intercellular movement, being necessary for the ability of diverse cell-to-cell movement proteins encoded by Begomoviruses (CaLCuV MP, Tobamoviruses (TVCV and TMV 30K protein and Potyviruses (TuMV P3N-PIPO to alter PD and thereby mediate virus cell-to-cell spread.

G2 phase arrest of cell cycle induced by ionizing radiation

International Nuclear Information System (INIS)

Liu Guangwei; Gong Shouliang

2002-01-01

The exposure of mammalian cells to X rays results in the prolongation of the cell cycle, including the delay or the arrest in G 1 , S and G 2 phase. The major function of G 1 arrest may be to eliminate the cells containing DNA damage and only occurs in the cells with wild type p53 function whereas G 2 arrest following ionizing radiation has been shown to be important in protecting the cells from death and occurs in all cells regardless of p53 status. So the study on G 2 phase arrest of the cell cycle induced by ionizing radiation has currently become a focus at radiobiological fields

Non-lethal effects of low- and high-LET radiation on cultured mammalian cells

International Nuclear Information System (INIS)

Walker, J.T.

1982-01-01

In analyzing post-irradiation growth kinetics of cultured mammalian cells, specifically T1-E human cells, this investigation shows that the shift in post-irradiation clone-size distributions toward small colonies is due to both radiation-induced division delay and increased generation times of the irradiated population. Evidence also indicates that the final shape of the final clone-size distribution is influenced by the age density distribution of the parent cells at the time of plating. From computer-generated delay time distributions it was determined that a large percentage of the parent population was found to be in the plateau phase at early growth times and evidence indicates that these cells may contribute heavily to the total population response to radiation

Fission yeast cells undergo nuclear division in the absence of spindle microtubules.

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Stefania Castagnetti

2010-10-01

Full Text Available Mitosis in eukaryotic cells employs spindle microtubules to drive accurate chromosome segregation at cell division. Cells lacking spindle microtubules arrest in mitosis due to a spindle checkpoint that delays mitotic progression until all chromosomes have achieved stable bipolar attachment to spindle microtubules. In fission yeast, mitosis occurs within an intact nuclear membrane with the mitotic spindle elongating between the spindle pole bodies. We show here that in fission yeast interference with mitotic spindle formation delays mitosis only briefly and cells proceed to an unusual nuclear division process we term nuclear fission, during which cells perform some chromosome segregation and efficiently enter S-phase of the next cell cycle. Nuclear fission is blocked if spindle pole body maturation or sister chromatid separation cannot take place or if actin polymerization is inhibited. We suggest that this process exhibits vestiges of a primitive nuclear division process independent of spindle microtubules, possibly reflecting an evolutionary intermediate state between bacterial and Archeal chromosome segregation where the nucleoid divides without a spindle and a microtubule spindle-based eukaryotic mitosis.

Decommissioning of the Risoe Hot Cell facility

International Nuclear Information System (INIS)

Carlsen, H.

1994-02-01

Concise description of progress in hot cell facility decommissioning at Risoe National Laboratory is presented. Removal of the large contaminated equipment has been completed, all the concrete cells have been finally cleaned. The total contamination left on the concrete walls is of the order of 1850 GBq. Preliminary smear tests proved the stack to be probably clean. The delay in project completion seems to be around 7 months, the remaining work being of rather conventional character. (EG)

Anti-HI can cause a severe delayed hemolytic transfusion reaction with hyperhemolysis in sickle cell disease patients.

Science.gov (United States)

Ibanez, Clara; Habibi, Anoosha; Mekontso-Dessap, Armand; Chadebech, Philippe; Chami, Btissam; Bierling, Philippe; Galactéros, Frédéric; Rieux, Claire; Nataf, Joëlle; Bartolucci, Pablo; Peyrard, Thierry; Pirenne, France

2016-07-01

Delayed hemolytic transfusion reaction (DHTR) is a life-threatening condition in sickle cell disease (SCD) patients that is frequently complicated by hyperhemolysis. Antibodies resulting from antigen disparity between donors of European ancestry and patients of African ancestry are common, but situations involving antibodies not classically of clinical significance are also encountered. Anti-HI is generally considered to be an innocuous naturally occurring antibody. We describe two cases of hyperhemolysis with anti-HI and provide details of the reported cases. Both SCD patients were polyimmunized and belonged to blood group B. They developed anti-HI that was reactive at 37°C, after the transfusion of group O red blood cell units matched for all known and produced antibodies classically considered to be clinically significant. Both patients developed DHTR with hyperhemolysis. In the first case, a pregnant woman, a second transfusion was unavoidable and the patient died from cardiac arrest. The state of the second patient improved without the need for further transfusion. Three other cases of DHTR with anti-HI have been described in the literature in SCD patients. The two additional cases reported here definitively demonstrate that anti-HI is dangerous in SCD patients. As a result, ABO-identical matching (including A1 status) must be considered in SCD patients with anti-HI. © 2016 AABB.

Effects of x-rays and bleomycin on cultured mammalian cells

International Nuclear Information System (INIS)

Masuda, Kouji; Takaki, Tosuke; Wakisaka, Shinichiro

1982-01-01

The cultured brain tumor cells and established cell lines, HeLa S3 and L5, were exposed to X-rays, with and without combinations of bleomycin, and the reproductive capacity and growth curves of these treated cells were assayed. No enhancement of the cell killing effect was observed when cells were treated with bleomycin following irradiation, while preliminary bleomycin treatment sensitized the cells to irradiation. No division delay was observed in cell reproductively surviving the bleomycin treatment, even though the concentrations of bleomycin were sufficient to reduce the survivals to less than 10%. An attempt to determine the conversion factor for evaluating X-ray doses in bleomycin equivalents failed because the order of the radiosensitivity of these cells was different from that of the sensitivity to bleomycin treatment. (author)

The effect of caffeine on X-ray-induced mitotic delay in normal human and ataxia-telangiectasia fibroblasts

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Zampetti-Bosseler, F.; Scott, D.

1985-01-01

The authors previously showed that radiation-sensitive fibroblasts from ataxia-telangiectasia (A-T) patients sustain less G 2 delay after X-irradiation than normal fibroblasts. Caffeine is known to reduce the amount of X-ray-induced delay in various mammalian cell types. It is proposed that A-T cells have an altered chromatin structure, similar to that of caffeine-treated normal cells and that this results in a failure of A-T cells to delay their progression through the cell cycle to allow time for DNA repair. The authors now show that caffeine treatment after X-irradiation reduces G 2 delay in both A-T and normal cells. The authors confirm the results previously obtained on lymphocytes that caffeine potentiates the chromosome-damaging effects of X-rays in both A-T and normal fibroblasts. These and other data suggest that the radiation responses of A-T cells and of caffeine-treated normal cells are caused by different mechanisms. (Auth.)

Immortalization of human myogenic progenitor cell clone retaining multipotentiality

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Hashimoto, Naohiro; Kiyono, Tohru; Wada, Michiko R.; Shimizu, Shirabe; Yasumoto, Shigeru; Inagawa, Masayo

2006-01-01

Human myogenic cells have limited ability to proliferate in culture. Although forced expression of telomerase can immortalize some cell types, telomerase alone delays senescence of human primary cultured myogenic cells, but fails to immortalize them. In contrast, constitutive expression of both telomerase and the E7 gene from human papillomavirus type 16 immortalizes primary human myogenic cells. We have established an immortalized primary human myogenic cell line preserving multipotentiality by ectopic expression of telomerase and E7. The immortalized human myogenic cells exhibit the phenotypic characteristics of their primary parent, including an ability to undergo myogenic, osteogenic, and adipogenic terminal differentiation under appropriate culture conditions. The immortalized cells will be useful for both basic and applied studies aimed at human muscle disorders. Furthermore, immortalization by transduction of telomerase and E7 represents a useful method by which to expand human myogenic cells in vitro without compromising their ability to differentiate

Adoptively transferred dendritic cells restore primary cell-mediated inflammatory competence to acutely malnourished weanling mice.

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Hillyer, Lyn; Whitley, Charlene; Olver, Amy; Webster, Michelle; Steevels, Tessa; Woodward, Bill

2008-02-01

Immune depression associated with prepubescent malnutrition underlies a staggering burden of infection-related morbidity. This investigation centered on dendritic cells as potentially decisive in this phenomenon. C57BL/6J mice, initially 19 days old, had free access for 14 days to a complete diet or to a low-protein formulation that induced wasting deficits of protein and energy. Mice were sensitized by i.p. injection of sheep red blood cells on day 9, at which time one-half of the animals in each dietary group received a simultaneous injection of 10(6) syngeneic dendritic cells (JAWS II). All mice were challenged with the immunizing antigen in the right hind footpad on day 13, and the 24-hour delayed hypersensitivity response was assessed as percentage increase in footpad thickness. The low-protein diet reduced the inflammatory immune response, but JAWS cells, which exhibited immature phenotypic and functional characteristics, increased the response of both the malnourished group and the controls. By contrast, i.p. injection of 10(6) syngeneic T cells did not influence the inflammatory immune response of mice subjected to the low-protein protocol. Antigen-presenting cell numbers limited primary inflammatory cell-mediated competence in this model of wasting malnutrition, an outcome that challenges the prevailing multifactorial model of malnutrition-associated immune depression. Thus, a new dendritic cell-centered perspective emerges regarding the cellular mechanism underlying immune depression in acute pediatric protein and energy deficit.

Glucose-ABL1-TOR Signaling Modulates Cell Cycle Tuning to Control Terminal Appressorial Cell Differentiation.

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Marroquin-Guzman, Margarita; Sun, Guangchao; Wilson, Richard A

2017-01-01

The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon-responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round of mitosis followed by autophagic cell death of the conidium. In contrast, Δabl1 mutant strains undergo multiple rounds of accelerated mitosis in elongated germ tubes, produce few appressoria, and are abolished for autophagy. Treating WT spores with glucose or 2-deoxyglucose phenocopied Δabl1. Inactivating TOR in Δabl1 mutants or glucose-treated WT strains restored appressorium formation by promoting mitotic arrest at G1/G0 via an appressorium- and autophagy-inducing cell cycle delay at G2/M. Collectively, this work uncovers a novel glucose-ABL1-TOR signaling axis and shows it engages two metabolic checkpoints in order to modulate cell cycle tuning and mediate terminal appressorial cell differentiation. We thus provide new molecular insights into TOR regulation and cell development in response to glucose.

Conversion of adipose-derived stem cells into natural killer-like cells with anti-tumor activities in nude mice.

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Hongxiu Ning

Full Text Available Efforts to develop peripheral blood-derived nature killer (NK cells into therapeutic products have been hampered by these cells' low abundance and histoincompatibility. On the other hand, derivation of NK-like cells from more abundant cell sources such as embryonic stem cells (ESCs and umbilical cord blood (UCB requires the selection of rare CD34+ cells. Thus, we sought to convert adipose-derived stem cells (ADSCs, which are abundant and natively CD34+, into NK-like cells. When grown in hematopoietic induction medium, ADSCs formed sphere clusters and expressed hematopoietic markers CD34, CD45, and KDR. Further induction in NK cell-specific medium resulted in a population of cells that expressed NK cell marker CD56, and thus termed ADSC-NK. Alternatively, the hematopoietically induced ADSCs were transduced with NK cell-specific transcription factor E4BP4 prior to induction in NK cell-specific medium. This latter population of cells, termed ADSC-NKE, expressed CD56 and additional NK cell markers such as CD16, CD94, CD158, CD314, FasL, and NKp46. ADSC-NKE was as potent as NK leukemia cell NKL in killing breast cancer cell MCF7 and prostate cancer cells DU145, PC3, LnCap, DuPro, C4-2 and CWR22, but exhibited no killing activity toward normal endothelial and smooth muscle cells. In nude mice test ADSC-NKE was able to significantly delay the progression of tumors formed by MCF7 and PC3. When injected into immunocompetent rats, ADSC-NKE was detectable in bone marrow and spleen for at least 5 weeks. Together, these results suggest that ADSCs can be converted into NK-like cells with anti-tumor activities.

Cell Adhesion Molecules Are Mediated by Photobiomodulation at 660 nm in Diabetic Wounded Fibroblast Cells

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Nicolette N. Houreld

2018-04-01

Full Text Available Diabetes affects extracellular matrix (ECM metabolism, contributing to delayed wound healing and lower limb amputation. Application of light (photobiomodulation, PBM has been shown to improve wound healing. This study aimed to evaluate the influence of PBM on cell adhesion molecules (CAMs in diabetic wound healing. Isolated human skin fibroblasts were grouped into a diabetic wounded model. A diode laser at 660 nm with a fluence of 5 J/cm2 was used for irradiation and cells were analysed 48 h post-irradiation. Controls consisted of sham-irradiated (0 J/cm2 cells. Real-time reverse transcription (RT quantitative polymerase chain reaction (qPCR was used to determine the expression of CAM-related genes. Ten genes were up-regulated in diabetic wounded cells, while 25 genes were down-regulated. Genes were related to transmembrane molecules, cell–cell adhesion, and cell–matrix adhesion, and also included genes related to other CAM molecules. PBM at 660 nm modulated gene expression of various CAMs contributing to the increased healing seen in clinical practice. There is a need for new therapies to improve diabetic wound healing. The application of PBM alongside other clinical therapies may be very beneficial in treatment.

Immunologic effects of hydroxyurea in sickle cell anemia.

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Lederman, Howard M; Connolly, Margaret A; Kalpatthi, Ram; Ware, Russell E; Wang, Winfred C; Luchtman-Jones, Lori; Waclawiw, Myron; Goldsmith, Jonathan C; Swift, Andrea; Casella, James F

2014-10-01

Susceptibility to encapsulated bacteria is well known in sickle cell disease (SCD). Hydroxyurea use is common in adults and children with SCD, but little is known about hydroxyurea's effects on immune function in SCD. Because hydroxyurea inhibits ribonucleotide reductase, causing cell cycle arrest at the G1-S interface, we postulated that hydroxyurea might delay transition from naive to memory T cells, with inhibition of immunologic maturation and vaccine responses. T-cell subsets, naive and memory T cells, and antibody responses to pneumococcal and measles, mumps, and rubella vaccines were measured among participants in a multicenter, randomized, double-blind, placebo-controlled trial of hydroxyurea in infants and young children with SCD (BABY HUG). Compared with placebo, hydroxyurea treatment resulted in significantly lower total lymphocyte, CD4, and memory T-cell counts; however, these numbers were still within the range of historical healthy controls. Antibody responses to pneumococcal vaccination were not affected, but a delay in achieving protective measles antibody levels occurred in the hydroxyurea group. Antibody levels to measles, mumps, and rubella showed no differences between groups at exit, indicating that effective immunization can be achieved despite hydroxyurea use. Hydroxyurea does not appear to have significant deleterious effects on the immune function of infants and children with SCD. Additional assessments of lymphocyte parameters of hydroxyurea-treated children may be warranted. No changes in current immunization schedules are recommended; however, for endemic disease or epidemics, adherence to accelerated immunization schedules for the measles, mumps, and rubella vaccine should be reinforced. Copyright © 2014 by the American Academy of Pediatrics.

Effect of dihydroartemisinin on the cell cycle progress of irradiated human cervical cancer cell line and its mechanism

International Nuclear Information System (INIS)

Chen Xialin; Ji Rong; Cao Jianping; Zhu Wei; Fan Sanjun; Wang Jianfang; Cao Jianping

2010-01-01

Objective: To observe the changes of cell cycle on cancer cells after dihydroartemisinin and X-ray irradiation. Methods: Human HeLa cells of cervical cancer with p53 mutation was used and human SiHa cells of cervical cancer with wild p53 was used as control. Flow cytometry was used to detect the effect of dihydroartemisinin (20 and 100 μmol/L) and irradiation (6 Gy)on cell cycle. Western blot was used to measure the levels of cell cycle protein. Results: G 2 arrest was observed in irradiated HeLa cells, which the proportion of cells in G 2 phase was increased from 14.45% to 73.58% after 6 Gy X-ray irradiation, but it was abrogated by dihydroartemisinin from 73. 58% to 48.31% in HeLa cells, and it had no change on the SiHa cells. The elevated Wee1 protein and the lowered Cyclin B1 protein were observed with the G 2 arrest severity. The expression of radiation-induced Wee1 protein was suppressed and the Cyclin B1 protein was increased after dihydroartemisinin treatment, which was in accordance with the abrogation of radiation-induced G 2 delay. Conclusions: The main effect of irradiation on cell cycle of p53 mutated HeLa cells is G 2 arrest. Dihydroartemisinin could abrogate it, which is associated with the changes of Wee1 protein and Cyclin B1 protein. In Siha cells, the main effect of irradiation on cell cycle is G 1 arrest, and dihydroartemisinin has no effect on it. (authors)

Inhibitory effects of hesperetin on Kv1.5 potassium channels stably expressed in HEK 293 cells and ultra-rapid delayed rectifier K(+) current in human atrial myocytes.

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Wang, Huan; Wang, Hong-Fei; Wang, Chen; Chen, Yu-Fang; Ma, Rong; Xiang, Ji-Zhou; Du, Xin-Ling; Tang, Qiang

2016-10-15

In the present study, the inhibitory effects of hesperetin (HSP) on human cardiac Kv1.5 channels expressed in HEK 293 cells and the ultra-rapid delayed rectifier K(+) current (Ikur) in human atrial myocytes were examined by using the whole-cell configuration of the patch-clamp techniques. We found that hesperetin rapidly and reversibly suppressed human Kv1.5 current in a concentration dependent manner with a half-maximal inhibition (IC50) of 23.15 μΜ with a Hill coefficient of 0.89. The current was maximally diminished about 71.36% at a concentration of 300μM hesperetin. Hesperetin significantly positive shifted the steady-state activation curve of Kv1.5, while negative shifted the steady-state inactivation curve. Hesperetin also accelerated the inactivation and markedly slowed the recovery from the inactivation of Kv1.5 currents. Block of Kv1.5 currents by hesperetin was in a frequency dependent manner. However, inclusion of 30μM hesperetin in pipette solution produced no effect on Kv1.5 channel current, while the current were remarkable and reversibly inhibited by extracellular application of 30μM hesperetin. We also found that hesperetin potently and reversibly inhibited the ultra-repaid delayed K(+) current (Ikur) in human atrial myocytes, which is in consistent with the effects of hesperetin on Kv1.5 currents in HEK 293 cells. In conclusion, hesperetin is a potent inhibitor of Ikur (which is encoded by Kv1.5), with blockade probably due to blocking of both open state and inactivated state channels from outside of the cell. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhanced effect of geldanamycin nanocomposite against breast cancer cells growing in vitro and as xenograft with vanquished normal cell toxicity

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Prabhu, Suma [Department of Radiation Biology and Toxicology, School of Life Sciences, Manipal University, Manipal 576 104, Karnataka (India); Ananthanarayanan, Preeta; Aziz, Sajida Kannangar [Department of Biotechnology, School of Life Sciences, Manipal University, Manipal 576 104, Karnataka (India); Rai, Sharada [Department of Pathology, Kasturba Medical College, Mangalore Campus, Manipal University, Mangalore 575 001, Karnataka (India); Mutalik, Srinivas [Department of Pharmaceutics, Manipal College of Pharmaceutical Sciences, Manipal University, Manipal 576 104, Karnataka (India); Sadashiva, Satish Rao Bola, E-mail: rao.satish@manipal.edu [Department of Radiation Biology and Toxicology, School of Life Sciences, Manipal University, Manipal 576 104, Karnataka (India)

2017-04-01

Despite enormous advances in remedies developed for breast cancer, an effective therapeutic strategy by targeting malignant cells with the least normal tissue toxicity is yet to be developed. Hsp90 is considered to be an important therapeutic target to inhibit cell proliferation. Geldanamycin (GDM), a potent inhibitor of Hsp90 was withdrawn from clinical trials due to its undesirable hepatotoxicity. We report a superparamagnetic iron oxide (SPION) based polymeric nanocomposite of GDM augmenting anticancer competence with decreased hepatic toxicity. The particle size of nanocomposite was ascertained to be 76 ± 10 nm with acceptable stability. A comparative dose dependent in vitro validation of cytotoxicity showed an enhanced cellular damage and necrosis in breast cancer (MCF-7) cell line at a low dose of 5.49 nM (in GDM nanocomposite) in contrast to 20 nM of pure GDM, while normal breast epithelial cells (MCF-10A) were least affected. Besides, in vivo study (in breast cancer xenografts) substantiated 2.7 fold delay in tumor progression mediated by redundancy in the downstream functions of p-Akt and MAPK-Erk leading to apoptosis with negligible hepatotoxicity. Pure GDM disrupted the function and morphology of liver with lesser therapeutic efficacy than the GDM nanocomposite. These findings deduce that GDM based polymeric magnetite nanocomposite play a vital role in efficacious therapy while vanquishing normal cells and hepatic toxicity and thereby promising it to be reinstated in clinics. - Highlights: • GDM nanocomposite shows selective cell kill of cancerous breast cells. • Nanocomposite delays the growth of tumor in comparison to pure GDM treatment. • GDM promotes apoptosis by down-regulation of p-Akt and MAPK-Erk. • GDM nanocomposite nullifies the hepatotoxicity generally exhibited by pure GDM.

Exogenous Hydrogen Peroxide Contributes to Heme Oxygenase-1 Delaying Programmed Cell Death in Isolated Aleurone Layers of Rice Subjected to Drought Stress in a cGMP-Dependent Manner.

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Wang, Guanghui; Xiao, Yu; Deng, Xiaojiang; Zhang, Heting; Li, Tingge; Chen, Huiping

2018-01-01

Hydrogen peroxide (H 2 O 2 ) is a reactive oxygen species (ROS) that plays a dual role in plant cells. Here, we discovered that drought (20% polyethylene glycol-6000, PEG)-triggered decreases of HO-1 transcript expression and HO activity. However, exogenous H 2 O 2 contributed toward the increase in HO-1 gene expression and activity of the enzyme under drought stress. Meanwhile, the HO-1 inducer hematin could mimic the effects of the H 2 O 2 scavengers ascorbic acid (AsA) and dimethylthiourea (DMTU) and the H 2 O 2 synthesis inhibitor diphenyleneiodonium (DPI) for scavenging or diminishing drought-induced endogenous H 2 O 2 . Conversely, the zinc protoporphyrin IX (ZnPPIX), an HO-1-specific inhibitor, reversed the effects of hematin. We further analyzed the endogenous H 2 O 2 levels and HO-1 transcript expression levels of aleurone layers treated with AsA, DMTU, and DPI in the presence of exogenous H 2 O 2 under drought stress, respectively. The results showed that in aleurone layers subjected to drought stress, when the endogenous H 2 O 2 level was inhibited, the effect of exogenous H 2 O 2 on the induction of HO-1 was enhanced. Furthermore, exogenous H 2 O 2 -activated HO-1 effectively enhanced amylase activity. Application of 8-bromoguanosine 3',5'-cyclic guanosine monophosphate (8-Br-cGMP) (the membrane permeable cGMP analog) promoted the effect of exogenous H 2 O 2 -delayed PCD of aleurone layers in response to drought stress. More importantly, HO-1 delayed the programmed cell death (PCD) of aleurone layers by cooperating with nitric oxide (NO), and the delayed effect of NO on PCD was achieved via mediation by cGMP under drought stress. In short, in rice aleurone layers, exogenous H 2 O 2 (as a signaling molecule) triggered HO-1 and delayed PCD via cGMP which possibly induced amylase activity under drought stress. In contrast, as a toxic by-product of cellular metabolism, the drought-generated H 2 O 2 promoted cell death.

Variability and Order in Cytoskeletal Dynamics of Motile Amoeboid Cells

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Hsu, Hsin-Fang; Bodenschatz, Eberhard; Westendorf, Christian; Gholami, Azam; Pumir, Alain; Tarantola, Marco; Beta, Carsten

2017-10-01

The chemotactic motion of eukaryotic cells such as leukocytes or metastatic cancer cells relies on membrane protrusions driven by the polymerization and depolymerization of actin. Here we show that the response of the actin system to a receptor stimulus is subject to a threshold value that varies strongly from cell to cell. Above the threshold, we observe pronounced cell-to-cell variability in the response amplitude. The polymerization time, however, is almost constant over the entire range of response amplitudes, while the depolymerization time increases with increasing amplitude. We show that cell-to-cell variability in the response amplitude correlates with the amount of Arp2 /3 , a protein that enhances actin polymerization. A time-delayed feedback model for the cortical actin concentration is consistent with all our observations and confirms the role of Arp2 /3 in the observed cell-to-cell variability. Taken together, our observations highlight robust regulation of the actin response that enables a reliable timing of cell movement.

3D Cell Culture in Alginate Hydrogels

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Therese Andersen

2015-03-01

Full Text Available This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent, and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.

Recovery of rat lens epithelial cells after total or partial x-irradiation

International Nuclear Information System (INIS)

Miller, R.C.; Riley, E.F.

1987-01-01

Irradiation of whole lenses interferes with the normal mitogenic response of lens cells to stimulation by mechanical wounding. Radiation exposure causes a delay and partial suppression of cells entering the S phase of the cell cycle. When cells are irradiated 1 day before wounding, DNA synthesis begins 20 hr after wounding and peaks 10 hr later. The return to a normal wound response is gradual when the time interval between irradiation and wounding is lengthened. By 28 days, essentially complete recovery of the wound response occurs. Mitosis shows a similar pattern of recovery. When half of the lens is irradiated 1 day before wounding, delay and suppression of the wound response in the irradiated half of the lens epithelium is observed. However, if 4 days elapse between irradiation and mechanical wounding, complete recovery of cells responding to the mitogenic stimulus occurs. Cells of the shielded half of the lens appear to compensate for the reduced number of irradiated cells entering S phase so that peak labelling of shielded cells is 70% compared with 50% for control lens cells. An evaluation of mitotic figures confirms faster recovery of the entire lens when only half the lens is irradiated. Complete recovery of the cellular response of partially irradiated lenses occurs in 4 days in contrast to almost 28 days for wholly irradiated lenses. (author)

Cell kinetics and acute lung injury

International Nuclear Information System (INIS)

Witschi, H.P.; Whitaker, M.S.

1987-01-01

In order to estimate whether acute lung injury is followed by a stereotype pattern of cell proliferation in the lungs, mice were treated with three cytostatic drugs: cyclophosphamide, busulfan, or 1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU). The alveolar labeling index was measured following drug administration with a pulse of 3 H-labeled thymidine and autoradiography. In cyclophosphamide treated animals, peak alveolar cell proliferation was seen 5 days after injection of the drug. In animals treated with busulfan or BCNU, proliferation was even more delayed (occurring 2 to 3 wks after administration). In contrast, with oleic acid, the highest alveolar cell labeling was found 2 days after intravenous administration. In animals exposed to a cytostatic drug, proliferation of type II alveolar cells was never a prominent feature; whereas, in animals treated with oleic acid there was an initial burst of type II cell proliferation. It was concluded that the patterns of pulmonary repair vary between chemical designed to interfere with DNA replication as compared to agents which produce acute lung damage such as oleic acid

Radiosensitivity of different human tumor cells lines grown as multicellular spheroids determined from growth curves and survival data

International Nuclear Information System (INIS)

Schwachoefer, J.H.C.; Crooijmans, R.P.; van Gasteren, J.J.; Hoogenhout, J.; Jerusalem, C.R.; Kal, H.B.; Theeuwes, A.G.

1989-01-01

Five human tumor cell lines were grown as multicellular tumor spheroids (MTS) to determine whether multicellular tumor spheroids derived from different types of tumors would show tumor-type dependent differences in response to single-dose irradiation, and whether these differences paralleled clinical behavior. Multicellular tumor spheroids of two neuroblastoma, one lung adenocarcinoma, one melanoma, and a squamous cell carcinoma of the oral tongue, were studied in terms of growth delay, calculated cell survival, and spheroid control dose50 (SCD50). Growth delay and cell survival analysis for the tumor cell lines showed sensitivities that correlated well with clinical behavior of the tumor types of origin. Similar to other studies on melanoma multicellular tumor spheroids our spheroid control dose50 results for the melanoma cell line deviated from the general pattern of sensitivity. This might be due to the location of surviving cells, which prohibits proliferation of surviving cells and hence growth of melanoma multicellular tumor spheroids. This study demonstrates that radiosensitivity of human tumor cell lines can be evaluated in terms of growth delay, calculated cell survival, and spheroid control dose50 when grown as multicellular tumor spheroids. The sensitivity established from these evaluations parallels clinical behavior, thus offering a unique tool for the in vitro analysis of human tumor radiosensitivity

Details Matter: Noise and Model Structure Set the Relationship between Cell Size and Cell Cycle Timing

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Felix Barber

2017-11-01

Full Text Available Organisms across all domains of life regulate the size of their cells. However, the means by which this is done is poorly understood. We study two abstracted “molecular” models for size regulation: inhibitor dilution and initiator accumulation. We apply the models to two settings: bacteria like Escherichia coli, that grow fully before they set a division plane and divide into two equally sized cells, and cells that form a bud early in the cell division cycle, confine new growth to that bud, and divide at the connection between that bud and the mother cell, like the budding yeast Saccharomyces cerevisiae. In budding cells, delaying cell division until buds reach the same size as their mother leads to very weak size control, with average cell size and standard deviation of cell size increasing over time and saturating up to 100-fold higher than those values for cells that divide when the bud is still substantially smaller than its mother. In budding yeast, both inhibitor dilution or initiator accumulation models are consistent with the observation that the daughters of diploid cells add a constant volume before they divide. This “adder” behavior has also been observed in bacteria. We find that in bacteria an inhibitor dilution model produces adder correlations that are not robust to noise in the timing of DNA replication initiation or in the timing from initiation of DNA replication to cell division (the C+D period. In contrast, in bacteria an initiator accumulation model yields robust adder correlations in the regime where noise in the timing of DNA replication initiation is much greater than noise in the C + D period, as reported previously (Ho and Amir, 2015. In bacteria, division into two equally sized cells does not broaden the size distribution.

Dual role of delay effects in a tumour-immune system.

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Yu, Min; Dong, Yueping; Takeuchi, Yasuhiro

2017-08-01

In this paper, a previous tumour-immune interaction model is simplified by neglecting a relatively weak direct immune activation by the tumour cells, which can still keep the essential dynamics properties of the original model. As the immune activation process is not instantaneous, we now incorporate one delay for the activation of the effector cells (ECs) by helper T cells (HTCs) into the model. Furthermore, we investigate the stability and instability regions of the tumour-presence equilibrium state of the delay-induced system with respect to two parameters, the activation rate of ECs by HTCs and the HTCs stimulation rate by the presence of identified tumour antigens. We show the dual role of this delay that can induce stability switches exhibiting destabilization as well as stabilization of the tumour-presence equilibrium. Besides, our results reveal that an appropriate immune activation time delay plays a significant role in control of tumour growth.

Mast cells play no role in the pathogenesis of postoperative ileus induced by intestinal manipulation.

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Gomez-Pinilla, Pedro J; Farro, Giovanna; Di Giovangiulio, Martina; Stakenborg, Nathalie; Némethova, Andrea; de Vries, Annick; Liston, Adrian; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Rodewald, Hans-Reimwer; Boeckxstaens, Guy E; Matteoli, Gianluca

2014-01-01

Intestinal manipulation (IM) during abdominal surgery results in intestinal inflammation leading to hypomotility or ileus. Mast cell activation is thought to play a crucial role in the pathophysiology of postoperative ileus (POI). However, this conclusion was mainly drawn using mast cell-deficient mouse models with abnormal Kit signaling. These mice also lack interstitial cells of Cajal (ICC) resulting in aberrant gastrointestinal motility even prior to surgery, compromising their use as model to study POI. To avoid these experimental weaknesses we took advantage of a newly developed knock-in mouse model, Cpa3(Cre/+) , devoid of mast cells but with intact Kit signaling. The role of mast cells in the development of POI and intestinal inflammation was evaluated assessing gastrointestinal transit and muscularis externa inflammation after IM in two strains of mice lacking mast cells, i.e. Kit(W-sh/W-sh) and Cpa3(Cre/+) mice, and by use of the mast cell stabilizer cromolyn. Kit(W-sh/W-sh) mice lack ICC networks and already revealed significantly delayed gastrointestinal transit even before surgery. IM did not further delay intestinal transit, but induced infiltration of myeloperoxidase positive cells, expression of inflammatory cytokines and recruitment of monocytes and neutrophils into the muscularis externa. On the contrary, Cpa3(Cre/+) mice have a normal network of ICC and normal gastrointestinal. Surprisingly, IM in Cpa3(Cre/+) mice caused delay in gut motility and intestinal inflammation as in wild type littermates mice (Cpa3(+/+) ). Furthermore, treatment with the mast cell inhibitor cromolyn resulted in an inhibition of mast cells without preventing POI. Here, we confirm that IM induced mast cell degranulation. However, our data demonstrate that mast cells are not required for the pathogenesis of POI in mice. Although there might be species differences between mouse and human, our results argue against mast cell inhibitors as a therapeutic approach to shorten POI.

Delayed hemolytic transfusion reaction/hyperhemolysis syndrome in children with sickle cell disease.

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Talano, Julie-An M; Hillery, Cheryl A; Gottschall, Jerome L; Baylerian, Diane M; Scott, J Paul

2003-06-01

Alloimmunization in patients with sickle cell disease (SCD) has a reported incidence of 5% to 36%. One complication of alloimmunization is delayed hemolytic transfusion reaction/hyperhemolysis (DHTR/H) syndrome, which has a reported incidence of 11%. In patients with SCD, clinical findings in DHTR/H syndrome occur approximately 1 week after the red blood cell (RBC) transfusion and include the onset of increased hemolysis associated with pain and profound anemia. The hemoglobin (Hb) often drops below pretransfusion levels. In many reported adult cases, the direct antiglobulin test (DAT) remains negative and no new alloantibody is detected as the cause for these transfusion reactions. To date, few pediatric cases have been reported with this phenomenon. The objective of this study was to describe the clinical and laboratory findings of a case series in children who had SCD and experienced a DHTR/H syndrome at our institution. An 11-year retrospective chart review of patients with discharge diagnosis of SCD and transfusion reaction was performed. DHTR/H syndrome was defined as the abrupt onset of signs and symptoms of accelerated hemolysis evidenced by an unexplained fall in Hb, elevated lactic dehydrogenase, elevated bilirubin above baseline, and hemoglobinuria, all occurring between 4 and 10 days after an RBC transfusion. Patient characteristics, time from transfusion, symptoms, reported DAT, new autoantibody or alloantibody formation, laboratory abnormalities, and complications were recorded. Patients with acute transfusion reactions were excluded. We encountered 7 patients who developed 9 episodes of DHTR/H syndrome occurring 6 to 10 days after RBC transfusion. Each presented with fever and hemoglobinuria. All but 1 patient experienced pain initially ascribed to vaso-occlusive crisis. The DAT was positive in only 2 of the 9 episodes. The presenting Hb was lower than pretransfusion levels in 8 of the 9 events. Severe complications were observed after the onset of

Ecotoxicological assessment of solar cell leachates: Copper indium gallium selenide (CIGS) cells show higher activity than organic photovoltaic (OPV) cells

Energy Technology Data Exchange (ETDEWEB)

Brun, Nadja Rebecca [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätsstrasse 16, CH-8092 Zürich (Switzerland); Wehrli, Bernhard [Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätsstrasse 16, CH-8092 Zürich (Switzerland); Fent, Karl, E-mail: karl.fent@fhnw.ch [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätsstrasse 16, CH-8092 Zürich (Switzerland)

2016-02-01

Despite the increasing use of photovoltaics their potential environmental risks are poorly understood. Here, we compared ecotoxicological effects of two thin-film photovoltaics: established copper indium gallium selenide (CIGS) and organic photovoltaic (OPV) cells. Leachates were produced by exposing photovoltaics to UV light, physical damage, and exposure to environmentally relevant model waters, representing mesotrophic lake water, acidic rain, and seawater. CIGS cell leachates contained 583 μg L{sup −1} molybdenum at lake water, whereas at acidic rain and seawater conditions, iron, copper, zinc, molybdenum, cadmium, silver, and tin were present up to 7219 μg L{sup −1}. From OPV, copper (14 μg L{sup −1}), zinc (87 μg L{sup −1}) and silver (78 μg L{sup −1}) leached. Zebrafish embryos were exposed until 120 h post-fertilization to these extracts. CIGS leachates produced under acidic rain, as well as CIGS and OPV leachates produced under seawater conditions resulted in a marked hatching delay and increase in heart edema. Depending on model water and solar cell, transcriptional alterations occurred in genes involved in oxidative stress (cat), hormonal activity (vtg1, ar), metallothionein (mt2), ER stress (bip, chop), and apoptosis (casp9). The effects were dependent on the concentrations of cationic metals in leachates. Addition of ethylenediaminetetraacetic acid protected zebrafish embryos from morphological and molecular effects. Our study suggests that metals leaching from damaged CIGS cells, may pose a potential environmental risk. - Highlights: • Photovoltaics may be disposed in the environment after usage. • Copper indium gallium selenide (CIGS) and organic (OPV) cells were compared. • Morphological and molecular effects were assessed in zebrafish embryos. • Environmental condition affected metal leaching and ecotoxicological activity. • Damaged CIGS cells pose higher risk to the environment than OPV cells.

Radiation damage and repair in cells and cell components. Part 2. Physical radiations and biological significance. Final report

International Nuclear Information System (INIS)

Fluke, D.J.

1984-08-01

The report comprises a teaching text, encompassing all physical radiations likely to be of biological interest, and the relevant biological effects and their significance. Topics include human radiobiology, delayed effects, radiation absorption in organisms, aqueous radiation chemistry, cell radiobiology, mutagenesis, and photobiology

Induction of early differentiation as a means of cell sterilization

International Nuclear Information System (INIS)

Wangenheim, K.-H. v.

1979-01-01

Investigations in plants suggest that cytoplasmic growth during mitotic delay induces an early attainment of terminal differentiation and cessation of mitotic activity. In mammals a direct demonstration of these processes is difficult. Plants and mammals show, however, a common phenomenon: Polyploidy does not usually reduce radiosensitivity as drastically as predicted by genetical considerations and certain experimental results. In root meristems of barley it is shown that cytoplasmic growth during mitotic delay increases the amount of cytoplasma per nuclear genome to approximately the same levels in tetraploid as in diploid cells. This results in the same loss, for both ploidy levels, of meristematic cells due to early differentiation. Apparently, under usual conditions, polyploidy is unable to significantly reduce radiosensitivity because the induction of differentiation processes is more important to radiation damage than the direct effect of genetic damage. Since the same basic principles also occur in mammals, it is suggested that early differentiation, and thereby cell sterilization, are induced in mammalian cells by the same mechanism as in plants. (Auth.)

Effects of low priming dose irradiation on cell cycle arrest of HepG2 cells caused by high dose irradiation

International Nuclear Information System (INIS)

Xia Jingguang; Jin Xiaodong; Chinese Academy of Sciences, Beijing; Li Wenjian; Wang Jufang; Guo Chuanling; Gao Qingxiang

2005-01-01

Human hepatoma cells hepG2 were irradiated twice by 60 Co γ-rays with a priming dose of 5 cGy and a higher dose of 3 Gy performed 4h or 8h after the low dose irradiation. Effects of the priming dose irradiation on cell cycle arrest caused by high dose were examined with flow cytometry. Cells in G 2 /M phase accumulated temporarily after the 5 cGy irradiation, and proliferation of tumor cells was promoted significantly by the low dose irradiation. After the 3 Gy irradiation, G 2 phase arrest occurred, and S phase delayed temporally. In comparison with 3 kGy irradiation only, the priming dose delivered 4h prior to the high dose irradiation facilitated accumulation of hepG2 cells in G 2 /M phase, whereas the priming dose delivered 8h prior to the high dose irradiation helped the cells to overcome G 2 arrest. It was concluded that effects of the priming dose treatment on cell cycle arrest caused by high dose irradiation were dependent on time interval between the two irradiations. (authors)

In vivo infection of IgG-containing cells by Jembrana disease virus during acute infection

International Nuclear Information System (INIS)

Desport, Moira; Tenaya, I.W. Masa; McLachlan, Alexander; McNab, Tegan J.; Rachmat, Judhi; Hartaningsih, Nining; Wilcox, Graham E.

2009-01-01

Jembrana disease virus (JDV) is an unusual bovine lentivirus which causes a non-follicular proliferation of lymphocytes, a transient immunosuppression and a delayed humoral response in infected Bali cattle in Indonesia. A double-immunofluorescent labeling method was developed to identify the subset of mononuclear cells in which the viral capsid protein could be detected. Viral antigen was present in pleomorphic centroblast-like cells which were identified as IgG-containing cells, including plasma cells, in lymphoid tissues. There was no evidence of infection of CD3 + T-cells or MAC387 + monocytes in tissues but large vacuolated cells with a macrophage-like morphology in the lung were found to contain viral antigen although they could not be shown conclusively to be infected. The tropism of JDV for mature IgG-containing cells may be relevant to understanding the pathogenesis of Jembrana disease, the delayed antibody responses and the genetic composition of this atypical lentivirus.

Degradation-mediated cellular traction directs stem cell fate in covalently crosslinked three-dimensional hydrogels

Science.gov (United States)

Khetan, Sudhir; Guvendiren, Murat; Legant, Wesley R.; Cohen, Daniel M.; Chen, Christopher S.; Burdick, Jason A.

2013-05-01

Although cell-matrix adhesive interactions are known to regulate stem cell differentiation, the underlying mechanisms, in particular for direct three-dimensional encapsulation within hydrogels, are poorly understood. Here, we demonstrate that in covalently crosslinked hyaluronic acid (HA) hydrogels, the differentiation of human mesenchymal stem cells (hMSCs) is directed by the generation of degradation-mediated cellular traction, independently of cell morphology or matrix mechanics. hMSCs within HA hydrogels of equivalent elastic moduli that permit (restrict) cell-mediated degradation exhibited high (low) degrees of cell spreading and high (low) tractions, and favoured osteogenesis (adipogenesis). Moreover, switching the permissive hydrogel to a restrictive state through delayed secondary crosslinking reduced further hydrogel degradation, suppressed traction, and caused a switch from osteogenesis to adipogenesis in the absence of changes to the extended cellular morphology. Furthermore, inhibiting tension-mediated signalling in the permissive environment mirrored the effects of delayed secondary crosslinking, whereas upregulating tension induced osteogenesis even in the restrictive environment.

Delayed Diagnosis: Giant Basal Cell Carcinoma of Scalp

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Didem Didar Balcı,

2008-07-01

Full Text Available Although basal cell carcinoma (BCC is the most common form of skin cancer, the scalp lesions of BCC have been rarely reported. Giant BCC is defined as a tumor larger than 5 cm in diameter and only 0.5-1 % of all BCCs achieve this size. We report a case of giant BCC on the scalp that was treated with topical coticosteroids and antifungal shampoo for five years. BCC should be considered in the differential diagnosis in erythematous plaque type lesions resistant to therapy with long duration localized on the scalp.

The role of CD4+ T cells in cell-mediated immunity to LCMV: studies in MHC class I and class II deficient mice

DEFF Research Database (Denmark)

Christensen, Jan Pravsgaard; Marker, O; Thomsen, Allan Randrup

1994-01-01

Parameters of the virus-specific T-cell response were analysed in order to dissect the contribution of CD4+ and CD8+ T cells to cell-mediated immunity to lymphocytic choriomeningitis virus. In MHC class II deficient mice, initial T-cell responsiveness was not impaired, but virus clearance...... was delayed, and virus-specific Td activity declined more rapidly. Furthermore, class I restricted Tc memory appeared to be impaired in these mice. To directly evaluate the role of CD4+ cells in virus clearance and T-cell mediated inflammation, MHC class I deficient mice were also studied. No virus...... exudate. This low-grade response was associated with some degree of virus control as organ titres were lower in these animals than in matched T-cell deficient nu/nu mice or class I deficient mice treated with anti-CD4 monoclonal antibody. This confirms that CD4+ cells are not needed to induce a virus...

Effect and Analysis of Sustainable Cell Rate using MPEG video Traffic in ATM Networks

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Sakshi Kaushal

2006-04-01

Full Text Available The broadband networks inhibit the capability to carry multiple types of traffic – voice, video and data, but these services need to be controlled according to the traffic contract negotiated at the time of the connection to maintain desired Quality of service. Such control techniques use traffic descriptors to evaluate its performance and effectiveness. In case of Variable Bit Rate (VBR services, Peak Cell Rate (PCR and its Cell Delay Variation Tolerance (CDVTPCR are mandatory descriptors. In addition to these, ATM Forum proposed Sustainable Cell Rate (SCR and its Cell delay variation tolerance (CDVTSCR. In this paper, we evaluated the impact of specific SCR and CDVTSCR values on the Usage Parameter Control (UPC performance in case of measured MPEG traffic for improving the efficiency

Autolyse the cell in order to save it? Inducing, then blocking, autolysis as a strategy for delaying cell death in the probiotic Lactobacillus reuteri.

Science.gov (United States)

Zimmerman, Tahl; Gyawali, Rabin; Ibrahim, Salam

2017-10-01

To examine whether choline and its derivatives can be used to preserve viable cells of Lactobacillus reuteri in autolytic models. A phosphate-induced autolytic model in de Man, Rogosa and Sharpe medium (MRS) was used. Viable cell counts were determined by plated on MRS-agar. Choline and hemicholinium-3 (HC-3) significantly blocked autolysis of L. reuteri at 360 mM and 4 mM, respectively. Viable cell counts corroborated these observations. Importantly, autolytically induced cells treated with choline and hemicholinium-3 were significantly more viable then even non-induced cells. Over-production of a known autolytic protein, spirosin, was not attenuated in the presence of choline and hemicholinium-3. Inducing autolysis and then blocking it with choline and its analogs is a promising approach for retaining the viability of L. reuteri cells.

Delayed hemolytic transfusion reaction presenting as a painful crisis in a patient with sickle cell anemia.

Science.gov (United States)

Fabron, A; Moreira, G; Bordin, J O

1999-01-07

Patients with sickle cell anemia (SCA) are frequently transfused with red blood cells (RBC). Recently we reported that the calculated risk of RBC alloimmunization per transfussed unit in Brazilian patients with SCA is 1.15%. We describe a delayed hemolytic transfusion reaction (DHTR) presenting as a painful crisis in a patient with SCA. A 35-year-old Brazilian female with homozygous SCA was admitted for a program of partial exchange transfusion prior to cholecystectomy. Her blood group was O RhD positive and no atypical RBC alloantibody was detected using the indirect antiglobulin technique. Pre-transfusional hemoglobin (Hb) was 8.7 g/dL and isovolumic partial exchange transfusion was performed using 4 units of ABO compatible packed RBC. Five days after the last transfusion she developed generalized joint pain and fever of 39 degrees C. Her Hb level dropped from 12.0 g/dL to 9.3 g/dL and the unconjugated bilirrubin level rose to 27 mmol/L. She was jaundiced and had hemoglobinuria. Hemoglobin electrophoresis showed 48.7% HbS, 46.6% HbA1, 2.7% HbA2, and 2.0% HbF. The patient's extended RBC phenotype was CDe, K-k+, Kp(a-b+), Fy(a-b-), M+N+s+, Le(a+b-), Di(a-). An RBC alloantibody with specificity to the Rh system (anti-c, titer 1:16.384) was identified by the indirect antiglobulin test. The Rh phenotype of the RBC used in the last packed RBC transfusion was CcDEe. The patient was discharged, asymptomatic, 7 days after admission.

Delayed esophageal perforation from stereotactic body radiation therapy for locally recurrent central nonsmall cell lung cancer

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Sandeep Sainathan

2014-01-01

Full Text Available Stereotactic body radiation therapy (SBRT is a novel form of external beam radiation therapy. It is used to treat early and locally recurrent nonsmall cell lung cancer (NSLC in medically inoperable patients. It uses high dose, hypofractionated radiotherapy, with targeting of the tumor by precise spatial localization, thus minimizing injury to surrounding tissues. It can be safely used to ablate NSLC in both central and peripheral locations. We present two cases of delayed esophageal perforation after SBRT for locally recurrent central NSLC. The perforations occurred several months after the therapy. They were treated with covered esophageal stents, with mortality, due to the perforation in one of the patients. SBRT should be judiciously used to ablate centrally located NSLC and patients who develop episodes of esophagitis during or after SBRT, need to be closely followed with endoscopy to look for esophageal ulcerations. These ulcers should be closely followed for healing as these may degenerate into full thickness perforations several months after SBRT.

Delayed chromosomal instability induced by DNA damage

International Nuclear Information System (INIS)

Morgan, W.F.; Marder, B.A.; Day, J.P.

1994-01-01

Cellular exposure to DNA damaging agents rapidly results in a dose dependent increase in chromosomal breakage and gross structural chromosomal rearrangements. Over recent years, evidence has been accumulating indicating genomic instability can manifest multiple generations after cellular exposure to physical and chemical DNA damaging agents. Genomic instability manifests in the progeny of surviving cells, and has been implicated in mutation, gene application, cellular transformation, and cell killing. To investigate chromosome instability following DNA damage, we have used fluorescence in situ hybridization to detect chromosomal rearrangements in a human/hamster somatic hybrid cell line following exposure to ionizing radiation. Delayed chromosomal instability was detected when multiple populations of uniquely arranged metaphases were observed in clonal isolates raised from single cells surviving X-irradiation many generations after exposure. At higher radiation doses, chromosomal instability was observed in a relatively high frequency of surviving clones and, in general, those clones showed delayed chromosome instability also showed reduced survival as measured by colony forming ability

Sources of Hematopoietic Stem and Progenitor Cells and Methods to Optimize Yields for Clinical Cell Therapy.

Science.gov (United States)

Panch, Sandhya R; Szymanski, James; Savani, Bipin N; Stroncek, David F

2017-08-01

Bone marrow (BM) aspirates, mobilized peripheral blood, and umbilical cord blood (UCB) have developed as graft sources for hematopoietic stem and progenitor cells (HSPCs) for stem cell transplantation and other cellular therapeutics. Individualized techniques are necessary to enhance graft HSPC yields and cell quality from each graft source. BM aspirates yield adequate CD34 + cells but can result in relative delays in engraftment. Granulocyte colony-stimulating factor (G-CSF)-primed BM HSPCs may facilitate faster engraftment while minimizing graft-versus-host disease in certain patient subsets. The levels of circulating HSPCs are enhanced using mobilizing agents, such as G-CSF and/or plerixafor, which act via the stromal cell-derived factor 1/C-X-C chemokine receptor type 4 axis. Alternate niche pathway mediators, including very late antigen-4/vascular cell adhesion molecule-1, heparan sulfate proteoglycans, parathyroid hormone, and coagulation cascade intermediates, may offer promising alternatives for graft enhancement. UCB grafts have been expanded ex vivo with cytokines, notch-ligand, or mesenchymal stromal cells, and most studies demonstrated greater quantities of CD34 + cells ex vivo and improved short-term engraftment. No significant changes were observed in long-term repopulating potential or in patient survival. Early phase clinical trials using nicotinamide and StemReginin1 may offer improved short- and long-term repopulating ability. Breakthroughs in genome editing and stem cell reprogramming technologies may hasten the generation of pooled, third-party HSPC grafts. This review elucidates past, present, and potential future approaches to HSPC graft optimization. Published by Elsevier Inc.

Highly flexible SRAM cells based on novel tri-independent-gate FinFET

Science.gov (United States)

Liu, Chengsheng; Zheng, Fanglin; Sun, Yabin; Li, Xiaojin; Shi, Yanling

2017-10-01

In this paper, a novel tri-independent-gate (TIG) FinFET is proposed for highly flexible SRAM cells design. To mitigate the read-write conflict, two kinds of SRAM cells based on TIG FinFETs are designed, and high tradeoff are obtained between read stability and speed. Both cells can offer multi read operations for frequency requirement with single voltage supply. In the first TIG FinFET SRAM cell, the strength of single-fin access transistor (TIG FinFET) can be flexibly adjusted by selecting five different modes to meet the needs of dynamic frequency design. Compared to the previous double-independent-gate (DIG) FinFET SRAM cell, 12.16% shorter read delay can be achieved with only 1.62% read stability decrement. As for the second TIG FinFET SRAM cell, pass-gate feedback technology is applied and double-fin TIG FinFETs are used as access transistors to solve the severe write-ability degradation. Three modes exist to flexibly adjust read speed and stability, and 68.2% larger write margin and 51.7% shorter write delay are achieved at only the expense of 26.2% increase in leakage power, with the same layout area as conventional FinFET SRAM cell.

Comparison of. gamma. i-irradiation-induced accumulation of ataxia telangiesctasia and control cells in G sub 2 phase

Energy Technology Data Exchange (ETDEWEB)

Bates, P.R. (Royal Brisbane Hospital, Herston (Australia)); Lavin, M.F. (Queensland Inst. of Medical Research, Brisbane (Australia))

1989-09-01

Recent reports from a number of laboratories have linked radiosensitivity in ataxia telangiectasia (AT) to a large and prolonged block of some cells in G{sub 2} phase. Previous results from this laboratory, largely with one Epstein-Barr virus-transformed A-T lymphoblastoid cell line, presented evidence for a dramatic increase in the number of cells in G{sub 2} phase over controls during a 24 h period post irradiation. We describe here a study of the effect of {gamma}-radiation on G{sub 2} phase delay in several A-T cell lines. Based on previous results with several cell lines 24 h post irradiation was selected as the optimum time to discriminate between G{sub 2} phase delay in control and A-T cells. All A-T homozygotes showed a signigicantly greater number of cells in G{sub 2} phase, 24 h post irradiation, than observed in controls. A more prolonged delay in G{sub 2} phase after irradiation was seen in different A-T cell types that included lymphoblastoid cells, fibroblasts and SV40-transformed fibroblasts. At the radiation dose used it was not possibel to distinguish A-T heterozygotes from controls (Author). 28 refs.; 2 figs.; 1 tab.

Response of the RIF-1 tumor in vitro and in C3H/Km mice to x-radiation (cell survival, regrowth delay, and tumor control), chemotherapeutic agents, and activated macrophages

International Nuclear Information System (INIS)

Brown, J.M.; Twentyman, P.R.; Zamvil, S.S.

1980-01-01

The radiation response of logarithmic growth phase and fed plateau phase RIF-1 cells in vitro was found to be characterized by D 0 values of 110 and 133 rads and extrapolation numbs of 36 and 28, respectively. The response of the tumor in vivo to X-irradiation in nonanesthetized mice showed a dependence on the tumor implantation site. In the leg muscle, the response indicated that most cells were at an intermediate level of oxygenation, whereas in the subcutaneous tissue of the flank, the response of the tumor indicated that it had a small fraction of hypoxic cells of maximum radioresistance. Misonidazole radiosensitized the leg-implanted tumor as measured both by cell survival and regrowth delay. The tumor was relatively insensitive to a single dose of 1,3-bis(2-chloroethyl)-1-nitrosourea, sensitive to a single dose of cis-platinum, and highly sensitive to a single dose of cyclophosphamide

Early death, late death and repair factor in three human tumour cell lines

International Nuclear Information System (INIS)

Courdi, A.; Gioanni, J.; Mari, D.; Chauvel, P.

1997-01-01

The in vivo colony method used to generate survival curves following exposure to ionizing irradiation allows to score large clones, representing surviving cells, and small colonies, representing late reproductive death. By subtraction, early-dying cells can be estimated. In the three human tumour cell lines examined, we have observed that early cell death is a major mode of action of irradiation. The contribution of early cell death to total mortality increases as the dose increases. Moreover, repair due to dose-splitting and delayed plating in densely-inhibited cells is not observed in early-dying cells. (authors)

A Statistical Approach for Gain Bandwidth Prediction of Phoenix-Cell Based Reflect arrays

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Hassan Salti

2018-01-01

Full Text Available A new statistical approach to predict the gain bandwidth of Phoenix-cell based reflectarrays is proposed. It combines the effects of both main factors that limit the bandwidth of reflectarrays: spatial phase delays and intrinsic bandwidth of radiating cells. As an illustration, the proposed approach is successfully applied to two reflectarrays based on new Phoenix cells.

Cell fate after mitotic arrest in different tumor cells is determined by the balance between slippage and apoptotic threshold

Energy Technology Data Exchange (ETDEWEB)

Galán-Malo, Patricia; Vela, Laura; Gonzalo, Oscar; Calvo-Sanjuán, Rubén; Gracia-Fleta, Lucía; Naval, Javier; Marzo, Isabel, E-mail: imarzo@unizar.es

2012-02-01

Microtubule poisons and other anti-mitotic drugs induce tumor death but the molecular events linking mitotic arrest to cell death are still not fully understood. We have analyzed cell fate after mitotic arrest produced by the microtubule-destabilizing drug vincristine in a panel of human tumor cell lines showing different response to vincristine. In Jurkat, RPMI 8226 and HeLa cells, apoptosis was triggered shortly after vincristine-induced mitotic arrest. However, A549 cells, which express a great amount of Bcl-x{sub L} and undetectable amounts of Bak, underwent mitotic slippage prior to cell death. However, when Bcl-x{sub L} gene was silenced in A549 cells, vincristine induced apoptosis during mitotic arrest. Another different behavior was found in MiaPaca2 cells, where vincristine caused death by mitotic catastrophe that switched to apoptosis when cyclin B1 degradation was prevented by proteasome inhibition. Overexpression of Bcl-x{sub L} or silencing Bax and Bak expression delayed the onset of apoptosis in Jurkat and RPMI 8226 cells, enabling mitotic slippage and endoreduplication. In HeLa cells, overexpression of Bcl-x{sub L} switched cell death from apoptosis to mitotic catastrophe. Mcl-1 offered limited protection to vincristine-induced cell death and Mcl-1 degradation was not essential for vincristine-induced death. All these results, taken together, indicate that the Bcl-x{sub L}/Bak ratio and the ability to degrade cyclin B1 determine cell fate after mitotic arrest in the different tumor cell types. Highlights: ► Vincristine induces cell death by apoptosis or mitotic catastrophe. ► Apoptosis-proficient cells die by apoptosis during mitosis upon vincristine treatment. ► p53wt apoptosis-deficient cells undergo apoptosis from a G1-like tetraploid state. ► p53mt apoptosis-deficient cells can survive and divide giving rise to 8N cells.

Immediate and delayed cochlear neuropathy after noise exposure in pubescent mice

DEFF Research Database (Denmark)

Jensen, Jane Bjerg; Lysaght, Andrew C; Liberman, M Charles

2015-01-01

Moderate acoustic overexposure in adult rodents is known to cause acute loss of synapses on sensory inner hair cells (IHCs) and delayed degeneration of the auditory nerve, despite the completely reversible temporary threshold shift (TTS) and morphologically intact hair cells. Our objective...... to 16 months post exposure. Mice exposed to neuropathic noise demonstrated immediate cochlear synaptopathy by 24 hours post exposure, and delayed neurodegeneration characterized by axonal retraction at 8 months, and spiral ganglion cell loss at 8-16 months post exposure. Although the damage...

Identification and functional analysis of endothelial tip cell-enriched genes.

Science.gov (United States)

del Toro, Raquel; Prahst, Claudia; Mathivet, Thomas; Siegfried, Geraldine; Kaminker, Joshua S; Larrivee, Bruno; Breant, Christiane; Duarte, Antonio; Takakura, Nobuyuki; Fukamizu, Akiyoshi; Penninger, Josef; Eichmann, Anne

2010-11-11

Sprouting of developing blood vessels is mediated by specialized motile endothelial cells localized at the tips of growing capillaries. Following behind the tip cells, endothelial stalk cells form the capillary lumen and proliferate. Expression of the Notch ligand Delta-like-4 (Dll4) in tip cells suppresses tip cell fate in neighboring stalk cells via Notch signaling. In DLL4(+/-) mouse mutants, most retinal endothelial cells display morphologic features of tip cells. We hypothesized that these mouse mutants could be used to isolate tip cells and so to determine their genetic repertoire. Using transcriptome analysis of retinal endothelial cells isolated from DLL4(+/-) and wild-type mice, we identified 3 clusters of tip cell-enriched genes, encoding extracellular matrix degrading enzymes, basement membrane components, and secreted molecules. Secreted molecules endothelial-specific molecule 1, angiopoietin 2, and apelin bind to cognate receptors on endothelial stalk cells. Knockout mice and zebrafish morpholino knockdown of apelin showed delayed angiogenesis and reduced proliferation of stalk cells expressing the apelin receptor APJ. Thus, tip cells may regulate angiogenesis via matrix remodeling, production of basement membrane, and release of secreted molecules, some of which regulate stalk cell behavior.

Context-dependent incremental timing cells in the primate hippocampus.

Science.gov (United States)

Sakon, John J; Naya, Yuji; Wirth, Sylvia; Suzuki, Wendy A

2014-12-23

We examined timing-related signals in primate hippocampal cells as animals performed an object-place (OP) associative learning task. We found hippocampal cells with firing rates that incrementally increased or decreased across the memory delay interval of the task, which we refer to as incremental timing cells (ITCs). Three distinct categories of ITCs were identified. Agnostic ITCs did not distinguish between different trial types. The remaining two categories of cells signaled time and trial context together: One category of cells tracked time depending on the behavioral action required for a correct response (i.e., early vs. late release), whereas the other category of cells tracked time only for those trials cued with a specific OP combination. The context-sensitive ITCs were observed more often during sessions where behavioral learning was observed and exhibited reduced incremental firing on incorrect trials. Thus, single primate hippocampal cells signal information about trial timing, which can be linked with trial type/context in a learning-dependent manner.

Monocyte-derived dendritic cells are essential for CD8+ T cell activation and anti-tumor responses after local immunotherapy

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Sabine eKuhn

2015-11-01

Full Text Available Tumors harbor several populations of dendritic cells with the ability to prime tumor-specific T cells. However, these T cells mostly fail to differentiate into armed effectors and are unable to control tumor growth. We have previously shown that treatment with immunostimulatory agents at the tumor site can activate anti-tumor immune responses, and is associated with the appearance of a population of monocyte-derived dendritic cells in the tumor and tumor-draining lymph node. Here we use dendritic cell or monocyte depletion and monocyte transfer to show that these monocyte-derived dendritic cells are critical to the activation of anti-tumor immune responses. Treatment with the immunostimulatory agents Monosodium Urate crystals and Mycobacterium smegmatis induced the accumulation of monocytes in the draining lymph node, their upregulation of CD11c and MHCII, and expression of iNOS, TNFα and IL12p40. Blocking monocyte entry into the lymph node and tumor through neutralization of the chemokine CCL2 or inhibition of Colony Stimulating Factor-1 receptor signaling prevented the generation of monocyte-derived dendritic cells, the infiltration of tumor-specific T cells into the tumor, and anti-tumor responses. In a reciprocal fashion, monocytes transferred into mice depleted of CD11c+ cells were sufficient to rescue CD8+ T cell priming in lymph node and delay tumor growth. Thus monocytes exposed to the appropriate conditions become powerful activators of tumor-specific CD8+ T cells and anti-tumor immunity.

Lack of WDR36 leads to preimplantation embryonic lethality in mice and delays the formation of small subunit ribosomal RNA in human cells in vitro.

Science.gov (United States)

Gallenberger, Martin; Meinel, Dominik M; Kroeber, Markus; Wegner, Michael; Milkereit, Philipp; Bösl, Michael R; Tamm, Ernst R

2011-02-01

Mutations in WD repeat domain 36 gene (WDR36) play a causative role in some forms of primary open-angle glaucoma, a leading cause of blindness worldwide. WDR36 is characterized by the presence of multiple WD40 repeats and shows homology to Utp21, an essential protein component of the yeast small subunit (SSU) processome required for maturation of 18S rRNA. To clarify the functional role of WDR36 in the mammalian organism, we generated and investigated mutant mice with a targeted deletion of Wdr36. In parallel experiments, we used RNA interference to deplete WDR36 mRNA in mouse embryos and cultured human trabecular meshwork (HTM-N) cells. Deletion of Wdr36 in the mouse caused preimplantation embryonic lethality, and essentially similar effects were observed when WDR36 mRNA was depleted in mouse embryos by RNA interference. Depletion of WDR36 mRNA in HTM-N cells caused apoptotic cell death and upregulation of mRNA for BAX, TP53 and CDKN1A. By immunocytochemistry, staining for WDR36 was observed in the nucleolus of cells, which co-localized with that of nucleolar proteins such as nucleophosmin and PWP2. In addition, recombinant and epitope-tagged WDR36 localized to the nucleolus of HTM-N cells. By northern blot analysis, a substantial decrease in 21S rRNA, the precursor of 18S rRNA, was observed following knockdown of WDR36. In addition, metabolic-labeling experiments consistently showed a delay of 18S rRNA maturation in WDR36-depleted cells. Our results provide evidence that WDR36 is an essential protein in mammalian cells which is involved in the nucleolar processing of SSU 18S rRNA.

Simian immunodeficiency virus infection induces severe loss of intestinal central memory T cells which impairs CD4+ T-cell restoration during antiretroviral therapy.

Science.gov (United States)

Verhoeven, D; Sankaran, S; Dandekar, S

2007-08-01

Simian immunodeficiency virus (SIV) infection leads to severe loss of intestinal CD4(+) T cells and, as compared to peripheral blood, restoration of these cells is slow during antiretroviral therapy (ART). Mechanisms for this delay have not been examined in context of which specific CD4(+) memory subsets or lost and fail to regenerate during ART. Fifteen rhesus macaques were infected with SIV, five of which received ART (FTC/PMPA) for 30 weeks. Viral loads were measured by real-time PCR. Flow cytometric analysis determined changes in T-cell subsets and their proliferative state. Changes in proliferative CD4(+) memory subsets during infection accelerated their depletion. This reduced the central memory CD4(+) T-cell pool and contributed to slow CD4(+) T-cell restoration during ART. There was a lack of restoration of the CD4(+) central memory and effector memory T-cell subsets in gut-associated lymphoid tissue during ART, which may contribute to the altered intestinal T-cell homeostasis in SIV infection.

PLD-Repair after ''holding'' of rodent cell cultures: A critical annotation

International Nuclear Information System (INIS)

Stevenson, A.F.G.; Lange, C.S.

1987-01-01

The radiosensitivity of cells in vitro has been reported to be influenced by culture-conditions both before and after exposure to ionising radiations. The effect of ''Stationary-Holding'' and/or delayed plating on the repair of potentially lethal damage (PLDR) are such examples. The so-called Stationary or Plateau-Phase of commonly used cell lines like the V79 are often quiescent (non-mitotic). The authors analysis of the V79 ''Plateau-Phase'' (S-phase cytocide through VrUdR incorporation with FuDR block and light exposure) reveals that the cultures have merely reached a state of maximal permissible density and are, in fact, in kinetic equilibrium with at least half the population of cells, even in densely confluent cultures, going through cycle. Attempts at holding the cells from cycling (through nutrient-depletion and serum-privation) were unsuccessful, although the turn-over-rate was reduced. Their assays for X-irradiated clonogenic survivors after attempted holding combined with delayed plating (DP) showed differences in the survival curves for exponentially growing (Log) and confluent cultures, Although DP improved survival in general, it abolished the shoulder in Log cultures. These observations may explain why most PLDR is seen in the second and lower survival-decades. The significance of the persistent cycling fraction in the interpretation of PLDR after delayed plating must be considered

Delayed postoperative radiation therapy in local control of squamous cell carcinoma of the tongue and floor of the mouth

Energy Technology Data Exchange (ETDEWEB)

Amar, Ali; Chedid, Helma Maria; Curioni, Otavio Alberto; Rapoport, Abrao, E-mail: arapoport@uol.com.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil); Dedivitis, Rogerio Aparecido; Cernea, Claudio Roberto; Brandao, Lenine Garcia [Hospital Heliopolis, Sao aulo, SP (Brazil)

2014-10-15

Objective: to evaluate the effect of time between surgery and postoperative radiation therapy on local recurrence of squamous cell carcinoma of the tongue and floor of the mouth. Methods: a total of 154 patients treated between 1996 and 2007 were selected considering local recurrence rate and time of the adjuvant radiotherapy. Results: local recurrence was diagnosed in 54 (35%) patients. Radiation therapy reduced the rate of local recurrences, although with no statistical significance. The time between surgery and initiation of postoperative radiotherapy did not significantly influence the risk of local recurrence in patients referred to adjuvant treatment (p=0.49). Conclusion: in the presence of risk factors for local recurrence, a short delay in starting the adjuvant radiation therapy does not contraindicate its performance. (author)

The potential role of ribosomal protein S5 on cell cycle arrest and initiation of murine erythroleukemia cell differentiation.

Science.gov (United States)

Matragkou, Christina N; Papachristou, Eleni T; Tezias, Sotirios S; Tsiftsoglou, Asterios S; Choli-Papadopoulou, Theodora; Vizirianakis, Ioannis S

2008-07-01

Evidence now exists to indicate that some ribosomal proteins besides being structural components of the ribosomal subunits are involved in the regulation of cell differentiation and apoptosis. As we have shown earlier, initiation of erythroid differentiation of murine erythroleukemia (MEL) cells is associated with transcriptional inactivation of genes encoding ribosomal RNAs and ribosomal proteins S5 (RPS5) and L35a. In this study, we extended these observations and investigated whether transfection of MEL cells with RPS5 cDNA affects the onset of initiation of erythroid maturation and their entrance in cell cycle arrest. Stably transfected MEL cloned cells (MEL-C14 and MEL-C56) were established and assessed for their capacity to produce RPS5 RNA transcript and its translated product. The impact of RPS5 cDNA transfection on the RPS5 gene expression patterns and the accumulation of RPS5 protein in inducible transfected MEL cells were correlated with their ability to: (a) initiate differentiation, (b) enter cell cycle arrest at G(1)/G(0) phase, and (c) modulate the level of cyclin-dependent kinases CDK2, CDK4, and CDK6. The data presented indicate that deregulation of RPS5 gene expression (constitutive expression) affects RPS5 protein level and delays both the onset of initiation of erythroid maturation and entrance in cell cycle arrest in inducer-treated MEL cells. 2008 Wiley-Liss, Inc.

Lack of direct evidence for a functional role of voltage-operated calcium channels in juxtaglomerular cells

DEFF Research Database (Denmark)

Kurtz, A; Skott, O; Chegini, S

1990-01-01

in patch-clamped nor in intact Furaester-loaded cells. Moreover, basal renin secretion from a preparation enriched in mouse juxtaglomerular cells and from rat glomeruli with attached juxtaglomerular cells was not inhibited when extracellular potassium was isoosmotically increased to 56 mmol/l. In mouse...... kidney slices, however, depolarizing potassium concentrations caused a delayed inhibition at 56 mmol/l and a delayed stimulation of renin secretion at 110 mmol/l. Taken together, our study does not provide direct evidence for a role of voltage-activated calcium channels in the regulation of calcium...

Reoxygenation of human coronary smooth muscle cells suppresses HIF-1{alpha} gene expression and augments radiation-induced growth delay and apoptosis

Energy Technology Data Exchange (ETDEWEB)

Grumann, T.; Arab, A.; Bode, C.; Hehrlein, C. [Dept. of Cardiology, Univ. Clinic of Freiburg (Germany); Guttenberger, R. [Dept. of Radiotherapy, Univ. Clinic of Freiburg (Germany)

2006-01-01

Background and Purpose: Catheter-based coronary brachytherapy with {beta}- and {gamma}-radiation is an evidence-based method to prevent restenosis after percutaneous transluminal coronary angioplasty (PTCA) and stent implantation, but the outcome may be PTCA are hypoxic. A lack of oxygen decreases the effect of low LET (linear energy transfer) irradiation. The authors assumed that reoxygenation of hypoxic human coronary smooth muscle cells (HCSMCs) improves the results of coronary brachytherapy. The expression of hypoxia-inducible factor 1{alpha} (HIF-1{alpha}) gene, and the rates of growth and apoptosis of hypoxic and reoxygenated HCSMCs after {gamma}-iradiation were therefore analyzed. Material and Methods: An in vitro model of megacolonies of HCSMCs was developed. After exposure to chronic hypoxia the HCSMCs were irradiated with graded doses of 2, 4, 8, and 16 Gy using a {sup 60}Co source either under hypoxia (pO{sub 2}<3 mmHg) or after reoxygenation (pO{sub 2}{approx}150 mmHg). RT-PCR (reverse transcription-polymerase chain reaction) analysis was used to quantify HIF-1{alpha} gene expression and the growth of HCSMC megacolonies was measured serially. The oxygen enhancement ratio (OER) was calculate from the specific growth delay. Apoptosis of HCSMCs was quantified by counting cells with specific DNA strand breaks using the TUNEL assy. Results: HIF-1{alpha} gene expression was markedly suppressed in reoxygenated cells versus hypoxic cells 30 min after {gamma}-irradiation at all radiation doses (158{+-}46% vs. 1,675{+-}1,211%; p<0.01). Apoptosis was markedly increased in reoxygenated HCSMCs. The OER was 1.8(95% CI[confidence interval]1.3-2.4). Therefore, reoxygenated HCSMCs require 44% less radiation dose to achieve the equivalent biological radiation effect compared to hypoxic HCSMCs. Conclusion: Reoxygenation of coronary smooth muscle cells should be considered an option to increase efficacy of coronary brachytherapy. This could be used to reduce radiation dose

CalpB modulates border cell migration in Drosophila egg chambers

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Kókai Endre

2012-07-01

Full Text Available Abstract Background Calpains are calcium regulated intracellular cysteine proteases implicated in a variety of physiological functions and pathological conditions. The Drosophila melanogaster genome contains only two genes, CalpA and CalpB coding for canonical, active calpain enzymes. The movement of the border cells in Drosophila egg chambers is a well characterized model of the eukaryotic cell migration. Using this genetically pliable model we can investigate the physiological role of calpains in cell motility. Results We demonstrate at the whole organism level that CalpB is implicated in cell migration, while the structurally related CalpA paralog can not fulfill the same function. The downregulation of the CalpB gene by mutations or RNA interference results in a delayed migration of the border cells in Drosophila egg chambers. This phenotype is significantly enhanced when the focal adhesion complex genes encoding for α-PS2 integrin ( if, β-PS integrin ( mys and talin ( rhea are silenced. The reduction of CalpB activity diminishes the release of integrins from the rear end of the border cells. The delayed migration and the reduced integrin release phenotypes can be suppressed by expressing wild-type talin-head in the border cells but not talin-headR367A, a mutant form which is not able to bind β-PS integrin. CalpB can cleave talin in vitro, and the two proteins coimmunoprecipitate from Drosophila extracts. Conclusions The physiological function of CalpB in border cell motility has been demonstrated in vivo. The genetic interaction between the CalpB and the if, mys, as well as rhea genes, the involvement of active talin head-domains in the process, and the fact that CalpB and talin interact with each other collectively suggest that the limited proteolytic cleavage of talin is one of the possible mechanisms through which CalpB regulates cell migration.

Characterization of the N-methoxyindole-3-carbinol (NI3C)–Induced Cell Cycle Arrest in Human Colon Cancer Cell Lines

DEFF Research Database (Denmark)

Neave, Antje S.; Sarup, Sussi; Seidelin, Michel

2005-01-01

Recent results have shown that indole-3-carbinol (I3C) inhibits the cellular growth of human cancer cell lines. In some cruciferous vegetables, another indole, N-methoxyindole-3-carbinol (NI3C), is found beside I3C. Knowledge about the biological effects of NI3C is limited. The aim of the present...... study was to show the effect of NI3C on cell growth of two human colon cancer cell lines, DLD-1 and HCT-116. For the first time it is shown that NI3C inhibits cellular growth of DLD-1 and HCT-116 and that NI3C is a more potent inhibitor of cell proliferation than I3C. In addition to the inhibition...... of cellular proliferation, NI3C caused an accumulation of HCT-116 cells in the G2/M phase, in contrast to I3C, which led to an accumulation of the colon cells in G0/G1 phase. Furthermore, NI3C delays the G1-S phase transition of synchronized HCT-116 cells. The indole-mediated cell-cycle arrest may be related...

Overexpression of catalase delays G0/G1- to S-phase transition during cell cycle progression in mouse aortic endothelial cells.

Science.gov (United States)

Onumah, Ogbeyalu E; Jules, George E; Zhao, Yanfeng; Zhou, LiChun; Yang, Hong; Guo, ZhongMao

2009-06-15

Although it is understood that hydrogen peroxide (H(2)O(2)) promotes cellular proliferation, little is known about its role in endothelial cell cycle progression. To assess the regulatory role of endogenously produced H(2)O(2) in cell cycle progression, we studied the cell cycle progression in mouse aortic endothelial cells (MAECs) obtained from mice overexpressing a human catalase transgene (hCatTg), which destroys H(2)O(2). The hCatTg MAECs displayed a prolonged doubling time compared to wild-type controls (44.0 +/- 4.7 h versus 28.6 +/- 0.8 h, pcatalase inhibitor, prevented the observed diminished growth rate in hCatTg MAECs. Inhibition of catalase activity with aminotriazole abrogated catalase overexpression-induced antiproliferative action. Flow cytometry analysis indicated that the prolonged doubling time was principally due to an extended G(0)/G(1) phase in hCatTg MAECs compared to the wild-type cells (25.0 +/- 0.9 h versus 15.9 +/- 1.4 h, pinhibitors, p21 and p27, which inhibit the Cdk activity required for the G(0)/G(1)- to S-phase transition. Knockdown of p21 and/or p27 attenuated the antiproliferative effect of catalase overexpression in MAECs. These results, together with the fact that catalase is an H(2)O(2) scavenger, suggest that endogenously produced H(2)O(2) mediates MAEC proliferation by fostering the transition from G(0)/G(1) to S phase.

β-Catenin promotes cell proliferation, migration, and invasion but induces apoptosis in renal cell carcinoma

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Yang CM

2017-02-01

Full Text Available Chun-ming Yang,1 Shan Ji,2 Yan Li,3 Li-ye Fu,3 Tao Jiang,3 Fan-dong Meng31Department of Urology, The First Affiliated Hospital, China Medical University, 2Department of Endocrinology, The Fifth People’s Hospital of Shenyang, 3Department of Biotherapy, Cancer Research Institute, The First Affiliated Hospital, China Medical University, Shenyang, ChinaAbstract: β-Catenin (CTNNB1 gene coding protein is a component of the Wnt signaling pathway that has been shown to play an important role in the formation of certain cancers. Abnormal accumulation of CTNNB1 contributes to most cancers. This research studied the involvement of β-catenin in renal cell carcinoma (RCC cell proliferation, apoptosis, migration, and invasion. Proliferation, cell cycle, and apoptosis were analyzed by using Cell Counting Kit-8 and by flow cytometry. Migration and invasion assays were measured by transwell analysis. Real-time polymerase chain reaction and Western blot analysis were used to detect the expression of CTNNB1, ICAM-1, VCAM-1, CXCR4, and CCL18 in RCC cell lines. It was found that CTNNB1 knockdown inhibited cell proliferation, migration, and invasion and induced apoptosis of A-498 cells. CTNNB1 overexpression promoted cell proliferation, migration, and invasion and inhibited apoptosis of 786-O cells. Moreover, knockdown of CTNNB1 decreased the levels of ICAM-1, VCAM-1, CXCR4, and CCL18 expression, but CTNNB1 overexpression increased the expression of ICAM-1, VCAM-1, CXCR4, and CCL18. Further in vivo tumor formation study in nude mice indicated that inhibition of CTNNB1 delayed the progress of tumor formation through inhibiting PCNA and Ki67 expression. These results indicate that CTNNB1 could act as an oncogene and may serve as a promising therapeutic strategy for RCC.Keywords: kidney cancer, oncogene, β-catenin, survival time, tumor migration-related protein

Regulation of cell cycle progression by cell-cell and cell-matrix forces

NARCIS (Netherlands)

Uroz, Marina; Wistorf, Sabrina; Serra-Picamal, Xavier; Conte, Vito; Sales-Pardo, Marta; Roca-Cusachs, Pere; Guimerà, Roger; Trepat, Xavier

2018-01-01

It has long been proposed that the cell cycle is regulated by physical forces at the cell-cell and cell-extracellular matrix (ECM) interfaces 1-12 . However, the evolution of these forces during the cycle has never been measured in a tissue, and whether this evolution affects cell cycle progression

Real-time monitoring of cisplatin-induced cell death.

Directory of Open Access Journals (Sweden)

Hamed Alborzinia

Full Text Available Since the discovery of cisplatin more than 40 years ago and its clinical introduction in the 1970s an enormous amount of research has gone into elucidating the mechanism of action of cisplatin on tumor cells. With a novel cell biosensor chip system allowing continuous monitoring of respiration, glycolysis, and impedance we followed cisplatin treatment of different cancer cell lines in real-time. Our measurements reveal a first effect on respiration, in all cisplatin treated cell lines, followed with a significant delay by interference with glycolysis in HT-29, HCT-116, HepG2, and MCF-7 cells but not in the cisplatin-resistant cell line MDA-MB-231. Most strikingly, cell death started in all cisplatin-sensitive cell lines within 8 to 11 h of treatment, indicating a clear time frame from exposure, first response to cisplatin lesions, to cell fate decision. The time points of most significant changes were selected for more detailed analysis of cisplatin response in the breast cancer cell line MCF-7. Phosphorylation of selected signal transduction mediators connected with cellular proliferation, as well as changes in gene expression, were analyzed in samples obtained directly from sensor chips at the time points when changes in glycolysis and impedance occurred. Our online cell biosensor measurements reveal for the first time the time scale of metabolic response until onset of cell death under cisplatin treatment, which is in good agreement with models of p53-mediated cell fate decision.

Origin of pluripotent germ cell tumours: the role of microenvironment during embryonic development

DEFF Research Database (Denmark)

Kristensen, David Møbjerg; Sonne, Si Brask; Ottesen, Anne Marie

2008-01-01

into virtually any type of tissue and form teratomas (non-seminomas). CIS cells display a close phenotypic similarity to fetal germ cells (primordial germ cells or gonocytes) suggesting an origin due to a developmental delay or arrest of differentiation of early germ cells. The pluripotency of these neoplasms...... in several tissue specific stem cells, such as TFAP2C (AP-2gamma) or KIT. CIS and seminomas highly express a number of pre-meiotic germ cell specific genes, which are down-regulated during development to non-seminomas, while the expression of other embryonic markers, such as SOX2, is up...

G2 block in Chinese hamster cells induced by x-irradiation, hyperthermia, cycloheximide, or actinomycin-D

International Nuclear Information System (INIS)

Dewey, W.C.; Highfield, D.P.

1976-01-01

The entry of cells into mitosis was monitored by shaking off mitotic cells from monolayer cultures. The location in G 2 of the x-ray transition point (TP), beyond which the cells were not delayed by x irradiation moved closer to mitosis as the dose was increased, i.e., at 10 min before prophase for 100 to 200 rad, and at 19 min for 30 to 60 rad. Treatment with cycloheximide (CH, 20 μg/ml) at the time of irradiation (50 to 100 rad) shifted the TP for x irradiation by 5 to 9 min toward mitosis. Calculations from these shifts in TP with radiation dose indicated that the logarithm of both the fraction of cells in G 2 not delayed by irradiation and the fraction beyond the TP for CH (located at 26 min before phophase for 5 to 50 μg/ml) not delayed by irradiation decreased linearly with dose (anti D 0 of 30 rad). Furthermore, inhibition of protein synthesis by CH, with or without a simultaneous treatment with actinomycin D (AMD), prevented repair of damage causing mitotic delay for a period of time equal to the duration of the CH treatment

Natural killer T (NKT cells accelerate Shiga toxin type 2 (Stx2 pathology in mice

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Fumiko eObata

2015-04-01

Full Text Available Shiga toxin-producing Escherichia coli (STEC is a leading cause of childhood renal disease He-molytic Uremic Syndrome (HUS. The involvement of renal cytokines and chemokines is sus-pected to play a critical role in disease progression. In current article, we tested the hypothesis that NKT cells are involved in Stx2-induced pathology in vivo. To address this hypothesis we compared Stx2 toxicity in WT and CD1 knockout (KO mice. In CD1KO mice, which lack nat-ural killer T (NKT cells, Stx2-induced pathologies such as weight loss, renal failure, and death were delayed. In WT mice, Stx2-specific selective increase in urinary albumin occurs in later time points, and this was also delayed in NKT cell deficient mice. NKT cell-associated cytokines such as IL-2, IL-4, IFN-γ and IL-17 were detected in kidney lysates of Stx2-injected WT mice with the peak around 36 h after Stx2 injection. In CD1KO, there was a delay in the kinetics, and increases in these cytokines were observed 60 h post Stx2 injection. These data suggest that NKT cells accelerate Stx2-induced pathology in mouse kidneys. To determine the mechanism by which NKT cells promote Stx2-associated disease, in vitro studies were performed using murine renal cells. We found that murine glomerular endothelial cells and podocytes express functional CD1d molecules and can present exogenous antigen to NKT cells. Moreover, we observed the direct interaction between Stx2 and the receptor Gb3 on the surface of mouse renal cells by 3D STORM-TIRF which provides single molecule imaging. Collectively, these data suggest that Stx2 binds to Gb3 on renal cells and leads to aberrant CD1d-mediated NKT cell activation. Therefore, strategies targeting NKT cells could have a significant impact on Stx2-associated renal pathology in STEC disease.

Natural killer T (NKT) cells accelerate Shiga toxin type 2 (Stx2) pathology in mice.

Science.gov (United States)

Obata, Fumiko; Subrahmanyam, Priyanka B; Vozenilek, Aimee E; Hippler, Lauren M; Jeffers, Tynae; Tongsuk, Methinee; Tiper, Irina; Saha, Progyaparamita; Jandhyala, Dakshina M; Kolling, Glynis L; Latinovic, Olga; Webb, Tonya J

2015-01-01

Shiga toxin-producing Escherichia coli (STEC) is a leading cause of childhood renal disease Hemolytic Uremic Syndrome (HUS). The involvement of renal cytokines and chemokines is suspected to play a critical role in disease progression. In current article, we tested the hypothesis that NKT cells are involved in Stx2-induced pathology in vivo. To address this hypothesis we compared Stx2 toxicity in WT and CD1 knockout (KO) mice. In CD1KO mice, which lack natural killer T (NKT) cells, Stx2-induced pathologies such as weight loss, renal failure, and death were delayed. In WT mice, Stx2-specific selective increase in urinary albumin occurs in later time points, and this was also delayed in NKT cell deficient mice. NKT cell-associated cytokines such as IL-2, IL-4, IFN-γ, and IL-17 were detected in kidney lysates of Stx2-injected WT mice with the peak around 36 h after Stx2 injection. In CD1KO, there was a delay in the kinetics, and increases in these cytokines were observed 60 h post Stx2 injection. These data suggest that NKT cells accelerate Stx2-induced pathology in mouse kidneys. To determine the mechanism by which NKT cells promote Stx2-associated disease, in vitro studies were performed using murine renal cells. We found that murine glomerular endothelial cells and podocytes express functional CD1d molecules and can present exogenous antigen to NKT cells. Moreover, we observed the direct interaction between Stx2 and the receptor Gb3 on the surface of mouse renal cells by 3D STORM-TIRF which provides single molecule imaging. Collectively, these data suggest that Stx2 binds to Gb3 on renal cells and leads to aberrant CD1d-mediated NKT cell activation. Therefore, strategies targeting NKT cells could have a significant impact on Stx2-associated renal pathology in STEC disease.

Mast cells play no role in the pathogenesis of postoperative ileus induced by intestinal manipulation.

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Pedro J Gomez-Pinilla

Full Text Available INTRODUCTION: Intestinal manipulation (IM during abdominal surgery results in intestinal inflammation leading to hypomotility or ileus. Mast cell activation is thought to play a crucial role in the pathophysiology of postoperative ileus (POI. However, this conclusion was mainly drawn using mast cell-deficient mouse models with abnormal Kit signaling. These mice also lack interstitial cells of Cajal (ICC resulting in aberrant gastrointestinal motility even prior to surgery, compromising their use as model to study POI. To avoid these experimental weaknesses we took advantage of a newly developed knock-in mouse model, Cpa3(Cre/+ , devoid of mast cells but with intact Kit signaling. DESIGN: The role of mast cells in the development of POI and intestinal inflammation was evaluated assessing gastrointestinal transit and muscularis externa inflammation after IM in two strains of mice lacking mast cells, i.e. Kit(W-sh/W-sh and Cpa3(Cre/+ mice, and by use of the mast cell stabilizer cromolyn. RESULTS: Kit(W-sh/W-sh mice lack ICC networks and already revealed significantly delayed gastrointestinal transit even before surgery. IM did not further delay intestinal transit, but induced infiltration of myeloperoxidase positive cells, expression of inflammatory cytokines and recruitment of monocytes and neutrophils into the muscularis externa. On the contrary, Cpa3(Cre/+ mice have a normal network of ICC and normal gastrointestinal. Surprisingly, IM in Cpa3(Cre/+ mice caused delay in gut motility and intestinal inflammation as in wild type littermates mice (Cpa3(+/+ . Furthermore, treatment with the mast cell inhibitor cromolyn resulted in an inhibition of mast cells without preventing POI. CONCLUSIONS: Here, we confirm that IM induced mast cell degranulation. However, our data demonstrate that mast cells are not required for the pathogenesis of POI in mice. Although there might be species differences between mouse and human, our results argue against mast

Effect of various 3H-thymidine concentrations on the kinetics of chinese hamster cell division

International Nuclear Information System (INIS)

Yuzhakov, V.V.; Lychev, V.A.

1985-01-01

A study of the asynchronous culture of Chinese hamster fibroblasts by autoradiography has shown that the pulse (15 min) incorporation of 3 H-thymidine in nuclear DNA influences the kinetics of labelled cell proliferation. The results obtained suggest that one of the early biological effects of the pulse incorporation of 3 H-thymidine is a delay in the occurrence of the first mitosis. With the concentration of 3 H-thymidine 37 kBq/ml the slowing down of the movement of labelled cells in the cycle is detected by a shift and overlapping of waves of labelled and unlabelled mitotic cells. In an increase of the concentration up to 370-925 kBq/ml the pattern of the curves of labelled mitotic cells is distorted. These distortions are well interpreted by the nature of change of the index of labelled and unlabelled mitotic cells. After an increase in 3 H-thymidine concentration from 37 up to 370-925 kBq/ml the mitotic activity of cells labelled at the end of S-phase decreases from 1 to o0.6-0.1% respectively. With the concentration of 925 kBq/ml for these cells incorporating 3 H-thymidine at the end of S-phase, a delay of the entry into mitosis reaches 6-8 h. Autoradiography data with assessment of granule density suggest that mitotic activity and the period of delay in the occurrence of mitosis depend on the dose of irradiation with intranuclear tritium

Induction of T helper 3 regulatory cells by dendritic cells infected with porcine reproductive and respiratory syndrome virus

International Nuclear Information System (INIS)

Silva-Campa, Erika; Flores-Mendoza, Lilian; Resendiz, Monica; Pinelli-Saavedra, Araceli; Mata-Haro, Veronica; Mwangi, Waithaka; Hernandez, Jesus

2009-01-01

Delayed development of virus-specific immune response has been observed in pigs infected with the porcine reproductive and respiratory syndrome virus (PRRSV). Several studies support the hypothesis that the PRRSV is capable of modulating porcine immune system, but the mechanisms involved are yet to be defined. In this study, we evaluated the induction of T regulatory cells by PRRSV-infected dendritic cells (DCs). Our results showed that PRRSV-infected DCs significantly increased Foxp3 + CD25 + T cells, an effect that was reversible by IFN-α treatment, and this outcome was reproducible using two distinct PRRSV strains. Analysis of the expressed cytokines suggested that the induction of Foxp3 + CD25 + T cells is dependent on TGF-β but not IL-10. In addition, a significant up-regulation of Foxp3 mRNA, but not TBX21 or GATA3, was detected. Importantly, our results showed that the induced Foxp3 + CD25 + T cells were able to suppress the proliferation of PHA-stimulated PBMCs. The T cells induced by the PRRSV-infected DCs fit the Foxp3 + CD25 + T helper 3 (Th3) regulatory cell phenotype described in the literature. The induction of this cell phenotype depended, at least in part, on PRRSV viability because IFN-α treatment or virus inactivation reversed these effects. In conclusion, this data supports the hypothesis that the PRRSV succeeds to establish and replicate in porcine cells early post-infection, in part, by inducing Th3 regulatory cells as a mechanism of modulating the porcine immune system.

Cell proliferation kinetics and radiation response in 9L tumor spheroids

Energy Technology Data Exchange (ETDEWEB)

Sweigert, S.E.

1984-05-01

Cell kinetic parameters, including population doubling-time, cell cycle time, and growth fraction, were measured in 9L gliosarcoma spheroids. These parameters were studied as the spheroids grew from 50 ..mu..m to over 900 ..mu..m in diameter. Experiments relating the cell kinetic parameters to the radiation response of 9L spheroids were also carried out. The major findings were that the average cell cycle time (T/sub c/), is considerably longer in large spheroids than in exponentially-growing monolayers, the radiosensitivity of noncycling (but still viable) cells in spheroids is not significantly different from that of cycling spheroid cells, and the radiation-induced division delay is approximately twice as long in spheroid cells as in monolayer cells given equal radiation doses. The cell loss factor for spheroids of various sizes was calculated, by using the measured kinetic parameters in the basic equations for growth of a cell population. 157 references, 6 figures, 3 tables.

Cell proliferation kinetics and radiation response in 9L tumor spheroids

International Nuclear Information System (INIS)

Sweigert, S.E.

1984-05-01

Cell kinetic parameters, including population doubling-time, cell cycle time, and growth fraction, were measured in 9L gliosarcoma spheroids. These parameters were studied as the spheroids grew from 50 μm to over 900 μm in diameter. Experiments relating the cell kinetic parameters to the radiation response of 9L spheroids were also carried out. The major findings were that the average cell cycle time (T/sub c/), is considerably longer in large spheroids than in exponentially-growing monolayers, the radiosensitivity of noncycling (but still viable) cells in spheroids is not significantly different from that of cycling spheroid cells, and the radiation-induced division delay is approximately twice as long in spheroid cells as in monolayer cells given equal radiation doses. The cell loss factor for spheroids of various sizes was calculated, by using the measured kinetic parameters in the basic equations for growth of a cell population. 157 references, 6 figures, 3 tables

Effect of pepleomycin combined with irradiation on cultured Chinese hamster V79 cells

International Nuclear Information System (INIS)

Saito, Tsutomu

1983-01-01

The combined effect of pepleomycin (PEP), a bleomycin derivative, with irradiation was investigated on cultured Chinese hamster V79 cells. An additive effect was observed when PEP and irradiation were given simultaneously. A time interval between PEP (50μg/ml for one hour) and subsequent irradiation (10 Gy) increased the survival, and it became maximum when the time interval exceeded 2 hours. PEP-induced potentially lethal damage (PLD) was recovered when trysinization was delayed, and this recovery increased the survival. When PEP was given at a time interval after initial irradiation, the survival was decreased to below that following simultaneous treatment of the two modalities, and it became minimum when the time interval was 5 to 6 hours. Cells in ''G 2 -block'' induced by 10 Gy irradiation were partially synchronized, and cells in G 2 -M phase were more sensitive to PEP than those in S phase. It was considered that cells became more sensitive to PEP when they were irradiated 5 to 6 hours previously. However, cells recovery at any cell age when trypsinization was delayed. The benefit of a time interval between the two modalities was decreased by this recovery. (author)

Exogenous Hydrogen Peroxide Contributes to Heme Oxygenase-1 Delaying Programmed Cell Death in Isolated Aleurone Layers of Rice Subjected to Drought Stress in a cGMP-Dependent Manner

Science.gov (United States)

Wang, Guanghui; Xiao, Yu; Deng, Xiaojiang; Zhang, Heting; Li, Tingge; Chen, Huiping

2018-01-01

Hydrogen peroxide (H2O2) is a reactive oxygen species (ROS) that plays a dual role in plant cells. Here, we discovered that drought (20% polyethylene glycol-6000, PEG)-triggered decreases of HO-1 transcript expression and HO activity. However, exogenous H2O2 contributed toward the increase in HO-1 gene expression and activity of the enzyme under drought stress. Meanwhile, the HO-1 inducer hematin could mimic the effects of the H2O2 scavengers ascorbic acid (AsA) and dimethylthiourea (DMTU) and the H2O2 synthesis inhibitor diphenyleneiodonium (DPI) for scavenging or diminishing drought-induced endogenous H2O2. Conversely, the zinc protoporphyrin IX (ZnPPIX), an HO-1-specific inhibitor, reversed the effects of hematin. We further analyzed the endogenous H2O2 levels and HO-1 transcript expression levels of aleurone layers treated with AsA, DMTU, and DPI in the presence of exogenous H2O2 under drought stress, respectively. The results showed that in aleurone layers subjected to drought stress, when the endogenous H2O2 level was inhibited, the effect of exogenous H2O2 on the induction of HO-1 was enhanced. Furthermore, exogenous H2O2-activated HO-1 effectively enhanced amylase activity. Application of 8-bromoguanosine 3′,5′-cyclic guanosine monophosphate (8-Br-cGMP) (the membrane permeable cGMP analog) promoted the effect of exogenous H2O2-delayed PCD of aleurone layers in response to drought stress. More importantly, HO-1 delayed the programmed cell death (PCD) of aleurone layers by cooperating with nitric oxide (NO), and the delayed effect of NO on PCD was achieved via mediation by cGMP under drought stress. In short, in rice aleurone layers, exogenous H2O2 (as a signaling molecule) triggered HO-1 and delayed PCD via cGMP which possibly induced amylase activity under drought stress. In contrast, as a toxic by-product of cellular metabolism, the drought-generated H2O2 promoted cell death. PMID:29449858

Magnetic resonance detection of CD34+ cells from umbilical cord blood using a 19F label

NARCIS (Netherlands)

L.E. Duinhouwer (Lucia); Van Rossum, B.J.M. (Bernard J. M.); S.T. van Tiel (Sandra); R.M. van der Werf (Ramon); R.Q. Doeswijk (Ronald); J.C. Haeck (Joost); Rombouts, E.W.J.C. (Elwin W. J. C.); M.N.D. Ter Borg (Mariëtte N. D.); G. Kotek (Gyula); E. Braakman (Eric); J.J. Cornelissen (Jan); M.R. Bernsen (Monique)

2015-01-01

textabstractImpaired homing and delayed recovery upon hematopoietic stem cell transplantation (HSCT) with hematopoietic stem cells (HSC) derived from umbilical cord blood (UCB) is a major problem. Tracking transplanted cells in vivo will be helpful to detect impaired homing at an early stage and

Chromosome condensation may enhance X-ray-related cell lethality in a temperature-sensitive mutant (tsBN2) of baby hamster kidney cells (BHK21)

International Nuclear Information System (INIS)

Sasaki, H.; Nishimoto, T.

1987-01-01

In the tsBN2 cell line, which has a temperature-sensitive defect in the regulatory mechanism for chromosome condensation, the lethal effect of X rays was enhanced by incubating the cells at a nonpermissive temperature (40 degrees C) following X irradiation. This enhancement was suppressed in the presence of cycloheximide, which inhibits induction of premature chromosome condensation. The findings obtained in the case of delayed incubation at 40 degrees C and in synchronized cells indicate that X-ray-related potentially lethal damage, which can be expressed by chromosome condensation, is produced in the cells at any stage of the cell cycle, but it is repairable for all cells except those at around the late G2-M phase, where chromosome condensation occurs at a permissive temperature (33.5 degrees C). These observations suggest that the high sensitivity of late G2-M cells to X rays is caused by the events associated with chromosome condensation

Modification of radiation-induced division delay by caffeine analogues and dibutyryl cyclic AMP

Energy Technology Data Exchange (ETDEWEB)

Kimler, B.F.; Leeper, D.B.; Snyder, M.H.; Rowley, R.; Schneiderman, M.H. (Thomas Jefferson Univ., Philadelphia, PA (USA). Hospital)

1982-01-01

The mitotic selection procedure for cell cycle analysis was utilized to investigate the concentration-dependent modification of x-radiation-induced division delay in Chinese hamster ovary (CHO) cells by methyl xanthines (caffeine, theophylline, and theobromine) and by dibutyryl cyclic AMP. The methyl xanthines (concentrations from 0.5 to 1000 ..mu..g/ml) all reduced radiation-induced division delay with the effect being linear between approximately 100 and 1000 ..mu..g/ml. After doses of 100-300 rad, delay was reduced by 75, 94 or 83 per cent at 1000 ..mu..g/ml for each drug, respectively. However, the addition of dibutyryl cyclic AMP had an opposite effect: radiation-induced delay was increased by the concentration range of 0.3 to 300 ..mu..g/ml. These results indicate that in mammalian cells the control of cell cycle progression and the modification of radiation-induced division delay are not simply related to intracellular levels of cyclic AMP. Rather, there appear to be at least two competing mechanisms which are differentially affected by caffeine analogues or by direct addition of dibutyryl cyclic AMP. The direct effect of caffeine and the methyl xanthines on membrane calcium permeability is considered.

Modification of radiation-induced division delay by caffeine analogues and dibutyryl cyclic AMP

International Nuclear Information System (INIS)

Kimler, B.F.; Leeper, D.B.; Snyder, M.H.; Rowley, R.; SChneiderman, M.H.

1982-01-01

The mitotic selection procedure for cell cycle analysis was utilized to investigate the concentration-dependent modification of x-radiation-induced division delay in Chinese hamster ovary (CHO) cells by methyl xanthines (caffeine, theophylline, and theobromine) and by dibutyryl cyclic AMP. The methyl xanthines (concentrations from 0.5 to 1000 μg/ml) all reduced radiation-induced division delay with the effect being linear between approximately 100 and 1000 μg/ml. After doses of 100-300 rad, delay was reduced by 75, 94 or 83 per cent at 1000 μg/ml for each drug, respectively. However, the addition of dibutyryl cyclic AMP had an opposite effect: radiation-induced delay was increased by the concentration range of 0.3 to 300 μg/ml. These results indicate that in mammalian cells the control of cell cycle progression and the modification of radiation-induced division delay are not simply related to intracellular levels of cyclic AMP. Rather, there appear to be at least two competing mechanisms which are differentially affected by caffeine analogues or by direct addition of dibutyryl cyclic AMP. The direct effect of caffeine and the methyl xanthines on membrane calcium permeability is considered. (author)

Tolerogenic dendritic cells from poorly compensated type 1 diabetes patients have decreased ability to induce stable antigen-specific T cell hyporesponsiveness and generation of suppressive regulatory T cells

DEFF Research Database (Denmark)

Dánova, Klara; Grohova, Anna; Strnadova, Pavla

2017-01-01

state of patients. tolDCs differentiated from both groups of patients acquired a regulatory phenotype and an anti-inflammatory profile. Interestingly, tolDCs from well-controlled patients expressed higher levels of inhibitory molecules IL-T3 and PD-L1. Additionally, glutamic acid decarboxylase (GAD)65......Tolerogenic dendritic cells (tolDCs) may offer an interesting intervention strategy to re-establish Ag-specific tolerance in autoimmune diseases, including type 1 diabetes (T1D). T1D results from selective destruction of insulin-producing b cells leading to hyperglycemia that, in turn, specifically...... suppressive abilities. The functionality of tolDCs was confirmed in the adoptive transfer model of NOD-SCID mice where tolDCs delayed diabetes onset. These results suggest that metabolic control of T1D affects the functional characteristics of tolDCs and subsequent effector T cell responses. Metabolic control...

Rho/ROCK signaling in regulation of corneal epithelial cell cycle progression.

Science.gov (United States)

Chen, Jian; Guerriero, Emily; Lathrop, Kira; SundarRaj, Nirmala

2008-01-01

The authors' previous study showed that the expression of a Rho-associated serine/threonine kinase (ROCK) is regulated during cell cycle progression in corneal epithelial cells. The present study was conducted to determine whether and how Rho/ROCK signaling regulates cell cycle progression. Rabbit corneal epithelial cells (RCECs) in culture were arrested in the G(0) phase of the cell cycle by serum deprivation and then allowed to re-enter the cell cycle in the presence or absence of the ROCK inhibitor (Y27632) in serum-supplemented medium. The number of cells in the S phase, the relative levels of specific cyclins and CDKs and their intracellular distribution, and the relative levels of mRNAs were determined by BrdU labeling, Western blot and immunocytochemical analyses, and real-time RT-PCR, respectively. ROCK inhibition delayed the progression of G(1) to S phase and led to a decrease in the number of RCECs entering the S phase between 12 and 24 hours from 31.5% +/- 4.5% to 8.1% +/- 2.6%. During the cell cycle progression, protein and mRNA levels of cyclin-D1 and -D3 and cyclin-dependent kinases CDK4 and CDK6 were significantly lower, whereas the protein levels of the CDK inhibitor p27(Kip1) were higher in ROCK-inhibited cells. Intracellular mRNA or protein levels of cyclin-E and protein levels of CDK2 were not significantly affected, but their nuclear translocation was delayed by ROCK inhibition. ROCK signaling is involved in cell cycle progression in RCECs, possibly by upregulation of cyclin-D1 and -D3 and CDK4, -6, and -2; nuclear translocation of CDK2 and cyclin-E; and downregulation of p27(Kip1).

Well-Controlled Cell-Trapping Systems for Investigating Heterogeneous Cell-Cell Interactions.

Science.gov (United States)

Kamiya, Koki; Abe, Yuta; Inoue, Kosuke; Osaki, Toshihisa; Kawano, Ryuji; Miki, Norihisa; Takeuchi, Shoji

2018-03-01

Microfluidic systems have been developed for patterning single cells to study cell-cell interactions. However, patterning multiple types of cells to understand heterogeneous cell-cell interactions remains difficult. Here, it is aimed to develop a cell-trapping device to assemble multiple types of cells in the well-controlled order and morphology. This device mainly comprises a parylene sheet for assembling cells and a microcomb for controlling the cell-trapping area. The cell-trapping area is controlled by moving the parylene sheet on an SU-8 microcomb using tweezers. Gentle downward flow is used as a driving force for the cell-trapping. The assembly of cells on a parylene sheet with round and line-shaped apertures is demonstrated. The cell-cell contacts of the trapped cells are then investigated by direct cell-cell transfer of calcein via connexin nanopores. Finally, using the device with a system for controlling the cell-trapping area, three different types of cells in the well-controlled order are assembled. The correct cell order rate obtained using the device is 27.9%, which is higher than that obtained without the sliding parylene system (0.74%). Furthermore, the occurrence of cell-cell contact between the three cell types assembled is verified. This cell-patterning device will be a useful tool for investigating heterogeneous cell-cell interactions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reproductive endocrine issues in men with sickle cell anemia.

Science.gov (United States)

Huang, A W; Muneyyirci-Delale, O

2017-07-01

In patients with sickle cell anemia, the sickling of red blood cells is known to cause end-organ damage by infarction. In some men who are affected by sickle cell anemia, the obstruction of venous outflow of the penis causes priapism, which could lead to erectile dysfunction. There is also evidence that the disease is linked to other reproductive issues in men-specifically delayed puberty, low testosterone, and sperm abnormalities-although the causes of these problems are less clear. Treatment of sickle cell anemia can have effects on the reproductive system as well. This review summarizes the findings from various publications pertaining to reproductive endocrinology, along with their conclusions and discrepancies. © 2017 American Society of Andrology and European Academy of Andrology.

Multi-tasking Sulf1/Sulf2 enzymes do not only facilitate extracellular cell signalling but also participate in cell cycle related nuclear events.

Science.gov (United States)

Krishnakumar, Kavithanjali; Chakravorty, Ishani; Foy, Wendy; Allen, Steve; Justo, Tiago; Mukherjee, Abir; Dhoot, Gurtej K

2018-03-01

This study demonstrates highly dynamic spatial and temporal pattern of SULF1/SULF2 expression in a number of neuronal cell types growing in normal culture medium that included their transient nuclear mobilisation. Their nuclear translocation became particularly apparent during cell proliferation as both SULF1/SULF2 demonstrated not only cell membrane associated expression, their known site of function but also transient nuclear mobilisation during nuclear cell division. Nuclear localisation was apparent not only by immunocytochemical staining but also confirmed by immunoblotting staining of isolated nuclear fractions of C6, U87 and N2A cells. Immunocytochemical analysis demonstrated rapid nuclear exit of both SULF1/SULF2 following cell division that was slightly delayed but not blocked in a fraction of the polyploid cells observed in C6 cells. The overexpression of both Sulf1 and Sulf2 genes in C6 and U87 cells markedly promoted in vitro growth of these cells accompanied by nuclear mobilisation while inhibition of both these genes inhibited cell proliferation with little or no nuclear SULF1/SULF2 mobilisation. SULF1/SULF2 activity in these cells thus demonstrated a clear co-ordination of extracellular cell signalling with nuclear events related to cell proliferation. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

Tumour cell lysate-loaded dendritic cell vaccine induces biochemical and memory immune response in castration-resistant prostate cancer patients.

Science.gov (United States)

Reyes, D; Salazar, L; Espinoza, E; Pereda, C; Castellón, E; Valdevenito, R; Huidobro, C; Inés Becker, M; Lladser, A; López, M N; Salazar-Onfray, F

2013-09-17

Recently, we produced a tumour antigen-presenting cells (TAPCells) vaccine using a melanoma cell lysate, called TRIMEL, as an antigen source and an activation factor. Tumour antigen-presenting cells induced immunological responses and increased melanoma patient survival. Herein, we investigated the effect of TAPCells loaded with prostate cancer cell lysates (PCCL) as an antigen source, and TRIMEL as a dendritic cell (DC) activation factor; which were co-injected with the Concholepas concholepas haemocyanin (CCH) as an adjuvant on castration-resistant prostate cancer (CRPC) patients. The lysate mix capacity, for inducing T-cell activation, was analysed by flow cytometry and Elispot. Delayed-type hypersensitivity (DTH) reaction against PCCL, frequency of CD8(+) memory T cells (Tm) in blood and prostate-specific antigen (PSA) levels in serum were measured in treated patients. The lysate mix induced functional mature DCs that were capable of activating PCCL-specific T cells. No relevant adverse reactions were observed. Six out of 14 patients showed a significant decrease in levels of PSA. DTH(+) patients showed a prolonged PSA doubling-time after treatment. Expansion of functional central and effector CD8(+) Tm were detected. Treatment of CRPC patients with lysate-loaded TAPCells and CCH as an adjuvant is safe: generating biochemical and memory immune responses. However, the limited number of cases requires confirmation in a phase II clinical trial.

Effects of X-irradiation on cell-cycle progression, induction of chromosomal aberrations and cell killing in ataxia telangiectasia (AT) fibroblasts

International Nuclear Information System (INIS)

Nagasawa, H.; Little, J.B.; Latt, S.A.; Lalande, M.E.

1985-01-01

Survival, cumulative labeling indices, chromosomal aberrations and cell-cycle distribution by flow microfluorometry (FMF) were studied in fibroblasts from normal and three ataxia telangiectasia (AT) families after X-irradiation during density-inhibition of growth and immediate release by subculture to low density. Homozygotic AT (proband) fibroblasts were very hypersensitive to cell killing by X-irradiation. Fibroblasts from AT heterozygotes (parents) were minimally hypersensitive, with D 0 's slightly lower than those for normal fibroblasts. There were three different response groups for a G 1 phase block induced by 400 rad of X-rays: (1) minimal or no G 1 block was observed in AT homozygote cell strains; (2) 10-20% of the cells were blocked in G 1 in normal cell strains; and (3) 50% or more of the cells were blocked in AT heterozygote strains. FMF profiles and cumulative labeling indices showed that homozygotic AT cells irradiated in plateau phase moved into the S-phase following subculture with no additional delay over non-irradiated controls. Homozygotic AT cells showed not only a 4-5 times higher frequency of X-ray-induced chromosomal aberrations than normal strains, but approximately 30% of these were of the chromatid-type. There were no differences in the frequency or type of X-ray-induced chromosomal aberrations between normal and heterozygotic AT cells. (orig.)

Cell Adhesions: Actin-Based Modules that Mediate Cell-Extracellular Matrix and Cell-Cell Interactions

Science.gov (United States)

Bachir, Alexia; Horwitz, Alan Rick; Nelson, W. James; Bianchini, Julie M.

2018-01-01

Cell adhesions link cells to the extracellular matrix (ECM) and to each other, and depend on interactions with the actin cytoskeleton. Both cell-ECM and cell-cell adhesion sites contain discrete, yet overlapping functional modules. These modules establish physical association with the actin cytoskeleton, locally modulate actin organization and dynamics, and trigger intracellular signaling pathways. Interplay between these modules generates distinct actin architectures that underlie different stages, types, and functions of cell-ECM and cell-cell adhesions. Actomyosin contractility is required to generate mature, stable adhesions, as well as sense and translate the mechanical properties of the cellular environment to changes in cell organization and behavior. In this chapter we discuss the organization and function of different adhesion modules and how they interact with the actin cytoskeleton. We highlight the molecular mechanisms of mechanotransduction in adhesions, and how adhesion molecules mediate crosstalk between cell-ECM and cell-cell adhesion sites. PMID:28679638

Phase resetting reveals network dynamics underlying a bacterial cell cycle.

Science.gov (United States)

Lin, Yihan; Li, Ying; Crosson, Sean; Dinner, Aaron R; Scherer, Norbert F

2012-01-01

Genomic and proteomic methods yield networks of biological regulatory interactions but do not provide direct insight into how those interactions are organized into functional modules, or how information flows from one module to another. In this work we introduce an approach that provides this complementary information and apply it to the bacterium Caulobacter crescentus, a paradigm for cell-cycle control. Operationally, we use an inducible promoter to express the essential transcriptional regulatory gene ctrA in a periodic, pulsed fashion. This chemical perturbation causes the population of cells to divide synchronously, and we use the resulting advance or delay of the division times of single cells to construct a phase resetting curve. We find that delay is strongly favored over advance. This finding is surprising since it does not follow from the temporal expression profile of CtrA and, in turn, simulations of existing network models. We propose a phenomenological model that suggests that the cell-cycle network comprises two distinct functional modules that oscillate autonomously and couple in a highly asymmetric fashion. These features collectively provide a new mechanism for tight temporal control of the cell cycle in C. crescentus. We discuss how the procedure can serve as the basis for a general approach for probing network dynamics, which we term chemical perturbation spectroscopy (CPS).

Cytokinetic effects of razoxane and relevance to radiopotentiation in a human adenocarcinoma cell line

International Nuclear Information System (INIS)

Norimah Yusof.

1982-01-01

Razoxane (+-1,2-bis (3,5-dioxopiperazin-1-yl)propane) or ICRF 159 has been shown to enhance the X-radiation sensitivity of a human colorectal adenocarcinoma cell line (HT29R) in culture if the cells were incubated with the drug for more than ten hours prior irradiation. Razoxane was shown not to interfere with repair of sublethal of potentially lethal damage of radiation. The radiosensitizing effect is therefore attributed to a reduced ability to accumulate such damage. As the effect was shown greater in exponential phase, which consists of greater proportion of dividing cells than plateau phase cells, it is believed that the drug (0.1 - 100 μg/ml) potentiates the effect of X-radiation in HT29R cells by pertubation in the cell cycle kinetics. Razoxane at low and high concentrations (5 and 100 μg/ml) was shown to delay the cell progression on cells entering mitosis. Chromosomes of drug-treated cells seemed to be unable to condense at the premitosis stage and cells with chromosomes resembling those in prophase were allowed to proceed through mitosis but progressed very slowly so that accumulation of mitotic cells were seen. Cells were than allowed to complete mitosis but frequently failed to undergo cytokinesis and subsequently produced many giant multinucleate cells. It is likely that the cells in mitosis and multinucleate cells are more radiosensitive. However, the mitotic delay was found to be reversible following progressive drug inactivation in the cells. Cells appeared to return to normal cell progression rate and division while the radiopotentiating effect was disappearing. The mechanism of drug action in inhibiting chromosome condensation was shown to involve the drug interference with histone H 1 phosphorylation. The inhibition of H 1 phosphorylation might reduce the cross-linking of the histone on DNA strands and thus preventing them from participating in supercoiling of the chromosome. (author)

P38 delta MAPK promotes breast cancer progression and lung metastasis by enhancing cell proliferation and cell detachment.

Science.gov (United States)

Wada, M; Canals, D; Adada, M; Coant, N; Salama, M F; Helke, K L; Arthur, J S; Shroyer, K R; Kitatani, K; Obeid, L M; Hannun, Y A

2017-11-23

The protein p38 mitogen-activated protein kinase (MAPK) delta isoform (p38δ) is a poorly studied member of the MAPK family. Data analysis from The Cancer Genome Atlas database revealed that p38δ is highly expressed in all types of human breast cancers. Using a human breast cancer tissue array, we confirmed elevation in cancer tissue. The breast cancer mouse model, MMTV-PyMT (PyMT), developed breast tumors with lung metastasis; however, mice deleted in p38δ (PyMT/p38δ -/- ) exhibited delayed primary tumor formation and highly reduced lung metastatic burden. At the cellular level, we demonstrate that targeting of p38δ in breast cancer cells, MCF-7 and MDA-MB-231 resulted in a reduced rate of cell proliferation. In addition, cells lacking p38δ also displayed an increased cell-matrix adhesion and reduced cell detachment. This effect on cell adhesion was molecularly supported by the regulation of the focal adhesion kinase by p38δ in the human breast cell lines. These studies define a previously unappreciated role for p38δ in breast cancer development and evolution by regulating tumor growth and altering metastatic properties. This study proposes MAPK p38δ protein as a key factor in breast cancer. Lack of p38δ resulted in reduced primary tumor size and blocked the metastatic potential to the lungs.

Pulmonary toxicity of cytostatic drugs: cell kinetics

International Nuclear Information System (INIS)

Witschi, H.; Godfrey, G.; Frome, E.; Lindenschmidt, R.C.

1987-01-01

Mice were treated with three cytostatic drugs: cyclophosphamide, busulfan, or 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). The alveolar labeling index was measured following drug administration with a pulse of 3 H-labeled thymidine and autoradiography. In cyclophosphamide-treated animals, peak alveolar cell proliferation was seen 5 days after injection of the drug. In animals treated with busulfan or BCNU, proliferation was even more delayed (occurring 2-3 weeks after administration). In contrast, with oleic acid, the highest alveolar cell labeling was found 2 days after intravenous administration. In animals exposed to a cytostatic drug, proliferation of type II alveolar cells was never a prominent feature whereas in animals treated with oleic acid there was an initial burst of type II cell proliferation. It is concluded that the patterns of pulmonary repair vary between chemicals designed to interfere with DNA replication as compared to agents which produce acute lung damage such as oleic acid

Age-Dependent Schwann Cell Phenotype Regulation Following Peripheral Nerve Injury.

Science.gov (United States)

Chen, Wayne A; Luo, T David; Barnwell, Jonathan C; Smith, Thomas L; Li, Zhongyu

2017-12-01

Schwann cells are integral to the regenerative capacity of the peripheral nervous system, which declines after adolescence. The mechanisms underlying this decline are poorly understood. This study sought to compare the protein expression of Notch, c-Jun, and Krox-20 after nerve crush injury in adolescent and young adult rats. We hypothesized that these Schwann cell myelinating regulatory factors are down-regulated after nerve injury in an age-dependent fashion. Adolescent (2 months old) and young adult (12 months old) rats (n = 48) underwent sciatic nerve crush injury. Protein expression of Notch, c-Jun, and Krox-20 was quantified by Western blot analysis at 1, 3, and 7 days post-injury. Functional recovery was assessed in a separate group of animals (n = 8) by gait analysis (sciatic functional index) and electromyography (compound motor action potential) over an 8-week post-injury period. Young adult rats demonstrated a trend of delayed onset of the dedifferentiating regulatory factors, Notch and c-Jun, corresponding to the delayed functional recovery observed in young adult rats compared to adolescent rats. Compound motor action potential area was significantly greater in adolescent rats relative to young adult rats, while amplitude and velocity trended toward statistical significance. The process of Schwann cell dedifferentiation following peripheral nerve injury shows different trends with age. These trends of delayed onset of key regulatory factors responsible for Schwann cell myelination may be one of many possible factors mediating the significant differences in functional recovery between adolescent and young adult rats following peripheral nerve injury.

Delayed coupling to feedback inhibition during a critical period for the integration of adult-born granule cells.

Science.gov (United States)

Temprana, Silvio G; Mongiat, Lucas A; Yang, Sung M; Trinchero, Mariela F; Alvarez, Diego D; Kropff, Emilio; Giacomini, Damiana; Beltramone, Natalia; Lanuza, Guillermo M; Schinder, Alejandro F

2015-01-07

Developing granule cells (GCs) of the adult dentate gyrus undergo a critical period of enhanced activity and synaptic plasticity before becoming mature. The impact of developing GCs on the activity of preexisting dentate circuits remains unknown. Here we combine optogenetics, acute slice electrophysiology, and in vivo chemogenetics to activate GCs at different stages of maturation to study the recruitment of local target networks. We show that immature (4-week-old) GCs can efficiently drive distal CA3 targets but poorly activate proximal interneurons responsible for feedback inhibition (FBI). As new GCs transition toward maturity, they reliably recruit GABAergic feedback loops that restrict spiking of neighbor GCs, a mechanism that would promote sparse coding. Such inhibitory loop impinges only weakly in new cohorts of young GCs. A computational model reveals that the delayed coupling of new GCs to FBI could be crucial to achieve a fine-grain representation of novel inputs in the dentate gyrus. Copyright © 2015 Elsevier Inc. All rights reserved.

Use of an adaptable cell culture kit for performing lymphocyte and monocyte cell cultures in microgravity

Science.gov (United States)

Hatton, J. P.; Lewis, M. L.; Roquefeuil, S. B.; Chaput, D.; Cazenave, J. P.; Schmitt, D. A.

1998-01-01

-based investigations simulating the conditions expected in the flight experiment. Several parameters including cell concentration, time between cell loading and activation, and storage temperature on cell survival were examined to characterise cell response and optimise the experiments to be flown aboard the Space Shuttle. Results indicate that the objectives of the experiments could be met with delays up to 5 days between cell loading into the hardware and initial in flight experiment activation, without the need for medium exchange. Experiment hardware of this kind, which is adaptable to a wide range of cell types and can be easily interfaced to different spacecraft facilities, offers the possibility for a wide range of experimenters successfully and easily to utilise future flight opportunities.

Cell-mediated immunity during syphilis. A review

Science.gov (United States)

Pavia, Charles S.; Folds, James D.; Baseman, Joel B.

1978-01-01

Evidence is presented which reinforces the complexity of the host-parasite interaction during the course of syphilis. Infection with Treponema pallidum evokes a complicated antibody response and an assortment of cell-mediated immune reactions in the host. It appears that humoral immunity plays a minor role towards the complete elimination of syphilitic infection while the cellular limb of the immune response may be an important host defence mechanism. Information now available indicates that a state of anergy, or immunosuppression, exists in the early stages of human and experimental rabbit syphilis based upon negative skin reactions to T. pallidum antigen(s), the abnormal histological appearance of lymphoid organs, and impaired in vitro lymphocyte reactivity. It is also evident that in the later stages of the disease cellular immunity becomes activated as delayed type skin reactions can normally be elicited in tertiary syphilitics and lymphocyte behaviour in cell culture appears normal. Several mechanisms have been invoked to explain the delay in an effective immune response against syphilitic infection and the duration of the disease: (1) a capsule-like substance on the outer surface of virulant T. pallidum may act as a barrier against treponemicidal antibody; (2) this material and other biological properties of virulent treponemes could enable spirochaetes to escape being engulfed by macrophages and other phagocytic cells; (3) antigenic competition among different treponemal antigens causing partial tolerance; (4) T. pallidum infection may bring about the elaboration of immunosuppressive substances of host or treponemal origin which inhibit the proper function of lymphocytes, macrophages, and other cell types. PMID:350348

Increased expression of cyclin B1 mRNA coincides with diminished G2-phase arrest in irradiated HeLa cells treated with staurosporine or caffeine

International Nuclear Information System (INIS)

Bernhard, E.J.; Maity, A.; McKenna, W.G.; Muschel, R.J.

1994-01-01

The irradiation of cells results in delayed progression through the G 2 phase of the cell cycle. Treatment of irradiated HeLa cells with caffeine greatly reduces the G 2 -phase delay, while caffeine does not alter progression of cells through the cell cycle in unirradiated cells. In this report we demonstrate that treatment of HeLa cells with the kinase inhibitor staurosporine, but not with the inhibitor H7, also results in a reduction of the G 2 -phase arrest after irradiation. Cell cycle progression in unirradiated cells is unaffected by 4.4 nM (2ng/ml) staurosporine, which releases the radiation-induced G 2 -phase arrest. In HeLa cells, the G 2 -phase delay after irradiation in S phase is accompanied by decreased expression of cyclin B1 mRNA. Coincident with the reduction in G 2 -phase delay, we observed an increase in cyclin B1 mRNA accumulation in irradiated, staurosporine-treated cells compared to cells treated with irradiation alone. Caffeine treatment of irradiated HeLa cells also resulted in an elevation in the levels of cyclin B1 message. These results support the hypothesis that diminished cyclin B1 mRNA levels influence G 2 -phase arrest to some degree. The findings that both staurosporine and caffeine treatments reverse the depression in cyclin B1 expression suggest that these two compounds may act on a common pathway of cell cycle control in response to radiation injury. 33 refs., 6 figs

A simple model of carcinogenic mutations with time delay and diffusion.

Science.gov (United States)

Piotrowska, Monika Joanna; Foryś, Urszula; Bodnar, Marek; Poleszczuk, Jan

2013-06-01

In the paper we consider a system of delay differential equations (DDEs) of Lotka-Volterra type with diffusion reflecting mutations from normal to malignant cells. The model essentially follows the idea of Ahangar and Lin (2003) where mutations in three different environmental conditions, namely favorable, competitive and unfavorable, were considered. We focus on the unfavorable conditions that can result from a given treatment, e.g. chemotherapy. Included delay stands for the interactions between benign and other cells. We compare the dynamics of ODEs system, the system with delay and the system with delay and diffusion. We mainly focus on the dynamics when a positive steady state exists. The system which is globally stable in the case without the delay and diffusion is destabilized by increasing delay, and therefore the underlying kinetic dynamics becomes oscillatory due to a Hopf bifurcation for appropriate values of the delay. This suggests the occurrence of spatially non-homogeneous periodic solutions for the system with the delay and diffusion.

Monoamine oxidase inhibitors l-deprenyl and clorgyline protect nonmalignant human cells from ionising radiation and chemotherapy toxicity.

LENUS (Irish Health Repository)

Seymour, C B

2003-11-17

l-Deprenyl (R-(-)-deprenyl, selegiline) is an inhibitor of monoamine oxidase-B (MAO-B) that is known to protect nerve cells from a variety of chemical and physical insults. As apoptosis is a common mechanism of radiation-induced cell death, the effect of l-deprenyl on the survival of cultured cells and tissue explants was studied following exposure to gamma radiation. The results obtained were compared with the effects of the less-selective MAO-B inhibitor pargyline and the MAO-A inhibitor clorgyline. l-Deprenyl at a concentration of 10(-9) M protected the nontumorigenic cell line (HaCaT) and normal human urothelial explants from the effects of cobalt-60 gamma radiation, but did not protect tumorigenic human cell lines HaCaT-ras, HPV-transfected human keratinocytes (HPV-G cells), or PC3. Human bladder carcinoma explants were not protected. Clorgyline showed a smaller protective effect of normal cells, whereas pargyline had no effect. Radiation-induced delayed effects (genomic instability measured as delayed cell death) were prevented in normal cells by l-deprenyl but, interestingly, deprenyl appeared to increase the amount of delayed death in the tumorigenic cell lines. Studies using l-deprenyl prior to the exposure of nonmalignant cells to cisplatin showed that cell death due to this agent was also reduced. Treatment of cultures of nontumorigenic cells with l-deprenyl or clorgyline significantly increased the levels of the protein Bcl-2 following irradiation, but there was no such effect on the already-elevated levels of this protein in the tumour samples. Since the Bcl-2 has been shown to be an inhibitor of apoptosis or programmed cell death, this would imply that the protective effects of l-deprenyl and clorgyline involve activation of antiapoptotic pathways within the normal cell. This hypothesis is supported by data showing reduced levels of apoptosis in HaCAT cells and in normal bladder explant cultures following treatment with l-deprenyl.

Meningeal mast cell-T cell crosstalk regulates T cell encephalitogenicity.

Science.gov (United States)

Russi, Abigail E; Walker-Caulfield, Margaret E; Guo, Yong; Lucchinetti, Claudia F; Brown, Melissa A

2016-09-01

GM-CSF is a cytokine produced by T helper (Th) cells that plays an essential role in orchestrating neuroinflammation in experimental autoimmune encephalomyelitis, a rodent model of multiple sclerosis. Yet where and how Th cells acquire GM-CSF expression is unknown. In this study we identify mast cells in the meninges, tripartite tissues surrounding the brain and spinal cord, as important contributors to antigen-specific Th cell accumulation and GM-CSF expression. In the absence of mast cells, Th cells do not accumulate in the meninges nor produce GM-CSF. Mast cell-T cell co-culture experiments and selective mast cell reconstitution of the meninges of mast cell-deficient mice reveal that resident meningeal mast cells are an early source of caspase-1-dependent IL-1β that licenses Th cells to produce GM-CSF and become encephalitogenic. We also provide evidence of mast cell-T cell co-localization in the meninges and CNS of recently diagnosed acute MS patients indicating similar interactions may occur in human demyelinating disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Stem cell therapy for ischemic heart diseases.

Science.gov (United States)

Yu, Hong; Lu, Kai; Zhu, Jinyun; Wang, Jian'an

2017-01-01

Ischemic heart diseases, especially the myocardial infarction, is a major hazard problem to human health. Despite substantial advances in control of risk factors and therapies with drugs and interventions including bypass surgery and stent placement, the ischemic heart diseases usually result in heart failure (HF), which could aggravate social burden and increase the mortality rate. The current therapeutic methods to treat HF stay at delaying the disease progression without repair and regeneration of the damaged myocardium. While heart transplantation is the only effective therapy for end-stage patients, limited supply of donor heart makes it impossible to meet the substantial demand from patients with HF. Stem cell-based transplantation is one of the most promising treatment for the damaged myocardial tissue. Key recent published literatures and ClinicalTrials.gov. Stem cell-based therapy is a promising strategy for the damaged myocardial tissue. Different kinds of stem cells have their advantages for treatment of Ischemic heart diseases. The efficacy and potency of cell therapies vary significantly from trial to trial; some clinical trials did not show benefit. Diverged effects of cell therapy could be affected by cell types, sources, delivery methods, dose and their mechanisms by which delivered cells exert their effects. Understanding the origin of the regenerated cardiomyocytes, exploring the therapeutic effects of stem cell-derived exosomes and using the cell reprogram technology to improve the efficacy of cell therapy for cardiovascular diseases. Recently, stem cell-derived exosomes emerge as a critical player in paracrine mechanism of stem cell-based therapy. It is promising to exploit exosomes-based cell-free therapy for ischemic heart diseases in the future. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Communicating the non-targeted effects of radiation from irradiated to non-irradiated cells

International Nuclear Information System (INIS)

Laiakis, E.C.; Morgan, W.F.

2005-01-01

For many years, the central dogma in radiobiology has been that energy deposited in the cell nucleus is responsible for the biological effects associated with radiation exposure. However, non-targeted and delayed effects of radiation have shifted this belief. The studies of radiation-induced genomic instability, the bystander and abscopal effects, clastogenic factors, and the Death Inducing Effect have dominated the interest of the radiobiology field of late. The passing of signals from irradiated to non-irradiated cells can be accomplished through cell-to-cell gap junction communication or secretion of molecules, which in turn can elicit a response through activation of signal transduction pathways. Proposed mediators of this phenotype include proteins involved with inflammation. Given their size and connection with oxidative stress, cytokines are an attractive candidate as mediators of the induction of the non-targeted effects of radiation. Here we review the evidence for a possible connection between these delayed non-targeted effects of radiation and the cytokine cascades associated with inflammation. (author)

Proteinase-Activated Receptor 1 (PAR1 regulates leukemic stem cell functions.

Directory of Open Access Journals (Sweden)

Nicole Bäumer

Full Text Available External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1-/- hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1-/- leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance.